TAMIFLU®
(oseltamivir phosphate) Capsules And For Oral Suspension
TAMIFLU (oseltamivir phosphate) is available as capsules containing 30 mg, 45 mg, or 75 mg oseltamivir for oral use, in the form of oseltamivir phosphate, and as a powder for oral suspension, which when constituted with water as directed contains 12 mg/mL oseltamivir base. In addition to the active ingredient, each capsule contains pregelatinized starch, talc, povidone K 30, croscarmellose sodium, and sodium stearyl fumarate. The 30 mg capsule shell contains gelatin, titanium dioxide, yellow iron oxide, and red iron oxide. The 45 mg capsule shell contains gelatin, titanium dioxide, and black iron oxide. The 75 mg capsule shell contains gelatin, titanium dioxide, yellow iron oxide, black iron oxide, and red iron oxide. Each capsule is printed with blue ink, which includes FD&C Blue No. 2 as the colorant. In addition to the active ingredient, the powder for oral suspension contains sorbitol, monosodium citrate, xanthan gum, titanium dioxide, tutti-frutti flavoring, sodium benzoate, and saccharin sodium.
Oseltamivir phosphate is a white crystalline solid with the chemical name (3R,4R,5S)-4acetylamino-5-amino-3(1-ethylpropoxy)-1-cyclohexene-1-carboxylic acid, ethyl ester, phosphate (1:1). The chemical formula is C16H28N2O4 (free base). The molecular weight is 312.4 for oseltamivir free base and 410.4 for oseltamivir phosphate salt. The structural formula is as follows:
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Last updated on RxList: 12/4/2008
TAMIFLU is indicated for the treatment of uncomplicated acute illness due to influenza infection in patients 1 year and older who have been symptomatic for no more than 2 days.
TAMIFLU is indicated for the prophylaxis of influenza in patients 1 year and older.
The following points should be considered before initiating treatment or prophylaxis with
TAMIFLU:
TAMIFLU may be taken with or without food (see CLINICAL PHARMACOLOGY: Pharmacokinetics). However, when taken with food, tolerability may be enhanced in some patients.
The recommended oral dose of TAMIFLU for treatment of influenza in adults and adolescents 13 years and older is 75 mg twice daily for 5 days. Treatment should begin within 2 days of onset of symptoms of influenza.
TAMIFLU is not indicated for treatment of influenza in pediatric patients younger than 1 year.
The recommended oral dose of TAMIFLU for pediatric patients 1 year and older is shown in Table 5. TAMIFLU for Oral Suspension may also be used by patients who cannot swallow a capsule. For pediatric patients who cannot swallow capsules,
TAMIFLU for Oral Suspension is the preferred formulation. If the for Oral Suspension product is not available, TAMIFLU Capsules may be opened and mixed with sweetened liquids such as regular or sugar-free chocolate syrup.
Table 5: Oral Dose of TAMIFLU for Treatment of Influenza
in Pediatric Patients by Weight
| Body Weight (kg) | Body Weight (lbs) | Recommended Dose for 5 Days | Number of Bottles of TAMIFLU for Oral Suspension Needed to Obtain the Recommended Doses for a 5 Day Regimen | Number of TAMIFLU Capsules Needed to Obtain the Recommended Doses for a 5 Day Regimen |
| ≤ 15 kg | ≤ 33 lbs | 30 mg twice daily | 1 | 10 TAMIFLU Capsules (30 mg) |
| >15 kg to 23 kg | >33 lbs to 51 lbs | 45 mg twice daily | 2 | 10 TAMIFLU Capsules (45 mg) |
| >23 kg to 40 kg | >51 lbs to 88 lbs | 60 mg twice daily | 2 | 20 TAMIFLU Capsules (30 mg) |
| >40 kg | >88 lbs | 75 mg twice daily | 3 | 10 TAMIFLU Capsules (75 mg) |
An oral dosing dispenser with 30 mg, 45 mg, and 60 mg graduations is provided with the oral suspension; the 75 mg dose can be measured using a combination of 30 mg and 45 mg. It is recommended that patients use this dispenser. In the event that the dispenser provided is lost or damaged, another dosing syringe or other device may be used to deliver the following volumes: 2.5 mL (1/2 tsp) for children ≤ 15 kg, 3.8 mL (3/4 tsp) for > 15 to 23 kg, 5.0 mL (1 tsp) for > 23 to 40 kg, and 6.2 mL (1 1/4 tsp) for > 40 kg.
The recommended oral dose of TAMIFLU for prophylaxis of influenza in adults and adolescents 13 years and older following close contact with an infected individual is 75 mg once daily for at least 10 days. Therapy should begin within 2 days of exposure. The recommended dose for prophylaxis during a community outbreak of influenza is 75 mg once daily. Safety and efficacy have been demonstrated for up to 6 weeks. The duration of protection lasts for as long as dosing is continued.
The safety and efficacy of TAMIFLU for prophylaxis of influenza in pediatric patients younger than 1 year of age have not been established.
The recommended oral dose of TAMIFLU for pediatric patients 1 year and older following close contact with an infected individual is shown in Table 6. TAMIFLU for Oral Suspension may also be used by patients who cannot swallow a capsule. For pediatric patients who cannot swallow capsules, TAMIFLU for Oral Suspension is the preferred formulation. If the for Oral Suspension product is not available, TAMIFLU Capsules may be opened and mixed with sweetened liquids such as regular or sugar-free chocolate syrup.
Table 6: Oral Dose of TAMIFLU for Prophylaxis of Influenza
in Pediatric Patients by Weight
| Body Weight (kg) | Body Weight (lbs) | Recommended Dose for10 Days | Number of Bottles of TAMIFLU for Oral Suspension Needed to Obtain the Recommended Doses for a 10 Day Regimen | Number of TAMIFLU Capsules Needed to Obtain the Recommended Doses for a 10 Day Regimen |
| ≤ 15 kg | ≤ 33 lbs | 30 mg once daily | 1 | 10 TAMIFLU Capsules (30 mg) |
| >15 kg to 23 kg | >33 lbs to 51 lbs | 45 mg once daily | 2 | 10 TAMIFLU Capsules (45 mg) |
| >23 kg to 40 kg | >51 lbs to 88 lbs | 60 mg once daily | 2 | 20 TAMIFLU Capsules (30 mg) |
| >40 kg | >88 lbs | 75 mg once daily | 3 | 10 TAMIFLU Capsules (75 mg) |
An oral dosing dispenser with 30 mg, 45 mg, and 60 mg graduations is provided with the oral suspension; the 75 mg dose can be measured using a combination of 30 mg and 45 mg. It is recommended that patients use this dispenser. In the event that the dispenser provided is lost or damaged, another dosing syringe or other device may be used to deliver the following volumes: 2.5 mL (1/2 tsp) for children ≤ 15 kg, 3.8 mL (3/4 tsp) for > 15 to 23 kg, 5.0 mL (1 tsp) for > 23 to 40 kg, and 6.2 mL (1 1/4 tsp) for > 40 kg.
Prophylaxis in pediatric patients following close contact with an infected individual is recommended for 10 days. Prophylaxis in patients 1 to 12 years of age has not been evaluated for longer than 10 days duration. Therapy should begin within 2 days of exposure.
No dose adjustment is recommended for patients with mild or moderate hepatic impairment (Child-Pugh score ≤ 9) (see CLINICAL PHARMACOLOGY: Pharmacokinetics: Special Populations).
For plasma concentrations of oseltamivir carboxylate predicted to occur following various dosing schedules in patients with renal impairment, see CLINICAL PHARMACOLOGY: Pharmacokinetics: Special Populations.
Dose adjustment is recommended for patients with creatinine clearance between 10 and 30 mL/min receiving TAMIFLU for the treatment of influenza. In these patients it is recommended that the dose be reduced to 75 mg of TAMIFLU once daily for 5 days. No recommended dosing regimens are available for patients undergoing routine hemodialysis and continuous peritoneal dialysis treatment with end-stage renal disease.
For the prophylaxis of influenza, dose adjustment is recommended for patients with creatinine clearance between 10 and 30 mL/min receiving TAMIFLU. In these patients it is recommended that the dose be reduced to 75 mg of TAMIFLU every other day or 30 mg TAMIFLU every day. No recommended dosing regimens are available for patients undergoing routine hemodialysis and continuous peritoneal dialysis treatment with endstage renal disease.
No dose adjustment is required for geriatric patients (see CLINICAL PHARMACOLOGY: Pharmacokinetics: Special Populations and PRECAUTIONS).
It is recommended that TAMIFLU for Oral Suspension be constituted by the pharmacist prior to dispensing to the patient:
NOTE: SHAKE THE TAMIFLU FOR ORAL SUSPENSION WELL BEFORE EACH USE.
The constituted TAMIFLU for Oral Suspension (12 mg/mL) should be used within 10 days of preparation; the pharmacist should write the date of expiration of the constituted suspension on a pharmacy label. The patient package insert and oral dispenser should be dispensed to the patient.
The following directions are provided for use only during emergency situations. These directions are not intended to be used if the FDA-approved, commercially manufactured TAMIFLU for Oral Suspension is readily available from wholesalers or the manufacturer.
Compounding an oral suspension with this procedure will provide one patient with enough medication for a 5-day course of treatment or a 10-day course of prophylaxis.
Commercially manufactured TAMIFLU for Oral Suspension (12 mg/mL) is the preferred product for pediatric and adult patients who have difficulty swallowing capsules or where lower doses are needed. In the event that TAMIFLU for Oral Suspension is not available, the pharmacist may compound a suspension (15 mg/mL) from TAMIFLU (oseltamivir phosphate) Capsules 75 mg using either of two vehicles: Cherry Syrup (Humco®) or Ora-Sweet® SF (sugar-free) (Paddock Laboratories). Other vehicles have not been studied. This compounded suspension should not be used for convenience or when the FDA-approved TAMIFLU for Oral Suspension is commercially available.
First, calculate the Total Volume of an oral suspension needed to be compounded and dispensed for each patient. The Total Volume required is determined by the weight of each patient. Refer to Table 7.
Table 7: Volume of an Oral Suspension (15 mg/mL) Needed to
be Compounded Based Upon the Patient's Weight
| Body Weight (kg) | Body Weight (lbs) | Total Volume to Compound per patient (mL) |
| ≤ 15 kg | ≤ 33 lbs | 30 mL |
| 16 to 23 kg | 34 to 51 lbs | 40 mL |
| 24 to 40 kg | 52 to 88 lbs | 50 mL |
| ≥ 41 kg | ≥ 89 lbs | 60 mL |
Second, determine the number of capsules and the amount of vehicle (Cherry Syrup or Ora-Sweet SF) that are needed to prepare the Total Volume (calculated from Table 7: 30 mL, 40 mL, 50 mL, or 60 mL) of compounded oral suspension (15 mg/mL). Refer to Table 8.
Table 8: Number of TAMIFLU 75 mg Capsules and Amount of Vehicle
(Cherry Syrup OR Ora-Sweet SF) Needed to Prepare the Total Volume of a Compounded
Oral Suspension (15 mg/mL)
| Total Volume of Compounded Oral Suspension needed to be Prepared | 30 mL | 40 mL | 50 mL | 60 mL |
| Required number of TAMIFLU 75 mg Capsules | 6 capsules (450 mg oseltamivir) | 8 capsules (600 mg oseltamivir) | 10 capsules (750 mg oseltamivir) | 12 capsules (900 mg oseltamivir) |
| Required volume of vehicle | 29 mL | 38.5 mL | 48 mL | 57 mL |
| Cherry Syrup (Humco) OR Ora-Sweet SF (Paddock Laboratories) |
Third, follow the procedure below for compounding the oral suspension (15 mg/mL) from TAMIFLU Capsules 75 mg
STORAGE OF THE PHARMACY-COMPOUNDED SUSPENSION:
Refrigeration: Stable for 5 weeks (35 days) when stored in a refrigerator at 2° to 8°C (36° to 46°F).
Room Temperature: Stable for five days (5 days) when stored at room temperature, 25°C (77°F).
Note: The storage conditions are based on stability studies of compounded oral suspensions, using the above mentioned vehicles, which were placed in amber glass and amber polyethyleneterephthalate (PET) bottles. Stability studies have not been conducted with other vehicles or bottle types.
Place a pharmacy label on the bottle that includes the patient's name, dosing instructions, and drug name and any other required information to be in compliance with all State and Federal Pharmacy Regulations. Refer to Table 9 for the proper dosing instructions.
Note: This compounding procedure results in a 15 mg/mL suspension, which is different from the commercially available TAMIFLU for Oral Suspension, which has a concentration of 12 mg/mL.
Table 9: Dosing Chart for Pharmacy-Compounded Suspension
from TAMIFLU Capsules 75 mg
| Body Weight (kg) | Body Weight (lbs) | Dose (mg) | Volume per Dose 15 mg/mL | Treatment Dose (for 5 days) | Prophylaxis Dose (for 10 days) |
| ≤ 15 kg | ≤ 33 lbs | 30 mg | 2 mL | 2 mL two times a day | 2 mL once daily |
| 16 to 23 kg | 34 to 51 lbs | 45 mg | 3 mL | 3 mL two times a day | 3 mL once daily |
| 24 to 40 kg | 52 to 88 lbs | 60 mg | 4 mL | 4 mL two times a day | 4 mL once daily |
| ≥ 41 kg | ≥ 89 lbs | 75 mg | 5 mL | 5 mL two times a day | 5 mL once daily |
| Note: 1 teaspoon = 5 mL | |||||
Consider dispensing the suspension with a graduated oral syringe for measuring small amounts of suspension. If possible, mark or highlight the graduation corresponding to the appropriate dose (2 mL, 3 mL, 4 mL, or 5 mL) on the oral syringe for each patient. The dosing device dispensed with the commercially available TAMIFLU for Oral Suspension should NOT be used with the compounded suspension since they have different concentrations.
30-mg capsules (30 mg free base equivalent of the phosphate salt): light yellow hard gelatin capsules. "ROCHE" is printed in blue ink on the light yellow body and "30 mg" is printed in blue ink on the light yellow cap. Available in blister packages of 10 (NDC 0004-0802-85).
45-mg capsules (45 mg free base equivalent of the phosphate salt): grey hard gelatin capsules. "ROCHE" is printed in blue ink on the grey body and "45 mg" is printed in blue ink on the grey cap. Available in blister packages of 10 (NDC 0004-0801-85).
75-mg capsules (75 mg free base equivalent of the phosphate salt): grey/light yellow hard gelatin capsules. "ROCHE" is printed in blue ink on the grey body and "75 mg" is printed in blue ink on the light yellow cap. Available in blister packages of 10 (NDC 0004-080085).
Store the capsules at 25°C (77°F); excursions permitted to 15° to 30°C(59° to 86°F). [See USP Controlled Room Temperature]
Supplied as a white powder blend for constitution to a white tutti-frutti–flavored suspension. Available in glass bottles containing approximately 33 mL of suspension after constitution. Each bottle delivers 25 mL of suspension equivalent to 300 mg oseltamivir base. Each bottle is supplied with a bottle adapter and 1 oral dispenser (NDC 0004-0810-95).
Store dry powder at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F). [See USP Controlled Room Temperature] Store constituted suspension under refrigeration at 2° to 8°C (36° to46°F). Do not freeze.
Distributed by: Roche Laboratories Inc., 340 Kingsland Stree, Nutley, New Jersey, NJ 17110 - 1199. Licensor: Gilead Sciences, Inc. Foster City, California 94404. Rev. August 2008. FDA Rev date: 9/25/2008
Last updated on RxList: 12/4/2008
A total of 1171 patients who participated in adult phase III controlled clinical trials for the treatment of influenza were treated with TAMIFLU. The most frequently reported adverse events in these studies were nausea and vomiting. These events were generally of mild to moderate degree and usually occurred on the first 2 days of administration. Less than 1% of subjects discontinued prematurely from clinical trials due to nausea and vomiting.
Adverse events that occurred with an incidence of ≥ 1% in 1440 patients taking placebo or TAMIFLU 75 mg twice daily in adult phase III treatment studies are shown in Table 3. This summary includes 945 healthy young adults and 495 "at risk" patients (elderly patients and patients with chronic cardiac or respiratory disease). Those events reported numerically more frequently in patients taking TAMIFLU compared with placebo were nausea, vomiting, bronchitis, insomnia, and vertigo.
A total of 4187 subjects (adolescents, healthy adults and elderly) participated in phase III prophylaxis studies, of whom 1790 received the recommended dose of 75 mg once daily for up to 6 weeks. Adverse events were qualitatively very similar to those seen in the treatment studies, despite a longer duration of dosing (see Table 3). Events reported more frequently in subjects receiving TAMIFLU compared to subjects receiving placebo in prophylaxis studies, and more commonly than in treatment studies, were aches and pains, rhinorrhea, dyspepsia and upper respiratory tract infections. However, the difference in incidence between TAMIFLU and placebo for these events was less than 1%. There were no clinically relevant differences in the safety profile of the 942 elderly subjects who received TAMIFLU or placebo, compared with the younger population.
Table 3: Most Frequent Adverse Events in Studies in Naturally
Acquired Influenza in Patients 13 Years of Age and Older
| Adverse Event | Treatment | Prophylaxis | ||
| Placebo N=716 |
Oseltamivir 75 mg bid N=724 |
Placebo/No Prophylaxisa N=1688 |
Oseltamivir 75 mg qd N=1790 |
|
| Nausea (without vomiting) | 40 (6%) | 72 (10%) | 56 (3%) | 129 (7%) |
| Vomiting | 21 (3%) | 68 (9%) | 16 (1%) | 39 (2%) |
| Diarrhea | 70 (10%) | 48 (7%) | 40 (2%) | 50 (3%) |
| Bronchitis | 15 (2%) | 17 (2%) | 22 (1%) | 15 (1%) |
| Abdominal pain | 16 (2%) | 16 (2%) | 25 (1%) | 37 (2%) |
| Dizziness | 25 (3%) | 15 (2%) | 21 (1%) | 24 (1%) |
| Headache | 14 (2%) | 13 (2%) | 306 (18%) | 326 (1%) |
| Cough | 12 (2%) | 9 (1%) | 119 (7%) | 94 (5%) |
| Insomnia | 6 (1%) | 8 (1%) | 15 (1%) | 22 (1%) |
| Vertigo | 4 (1%) | 7 (1%) | 4 (<1%) | 4 (<1%) |
| Fatigue | 7 (1%) | 7 (1%) | 163 (10%) | 139 (8%) |
| a The majority of subjects received placebo; 254 subjects from a randomized, open-label post exposure prophylaxis study in households did not receive placebo or prophylaxis therapy. | ||||
Adverse events included are: all events reported in the treatment studies with frequency ≥ 1% in the oseltamivir 75 mg bid group.
Additional adverse events occurring in < 1% of patients receiving TAMIFLU for treatment included unstable angina, anemia, pseudomembranous colitis, humerus fracture, pneumonia, pyrexia, and peritonsillar abscess.
A total of 1032 pediatric patients aged 1 to 12 years (including 698 otherwise healthy pediatric patients aged 1 to 12 years and 334 asthmatic pediatric patients aged 6 to 12 years) participated in phase III studies of TAMIFLU given for the treatment of influenza. A total of 515 pediatric patients received treatment with TAMIFLU for Oral Suspension.
Adverse events occurring in ≥ 1% of pediatric patients receiving TAMIFLU treatment are listed in Table 4. The most frequently reported adverse event was vomiting. Other events reported more frequently by pediatric patients treated with TAMIFLU included abdominal pain, epistaxis, ear disorder, and conjunctivitis. These events generally occurred once and resolved despite continued dosing. They did not cause discontinuation of drug in the vast majority of cases.
The adverse event profile in adolescents is similar to that described for adult patients and pediatric patients aged 1 to 12 years.
Pediatric patients aged 1 to 12 years participated in a postexposure prophylaxis study in households, both as index cases (134) and as contacts (222). Gastrointestinal events were the most frequent, particularly vomiting. The adverse events noted were consistent with those previously observed in pediatric treatment studies (see Table 4).
Table 4: Most Frequent Adverse Events Occurring in Children
Aged 1 to 12 Years in Studies in Naturally Acquired Influenza
| Adverse Event | TreatmentTrialsa | Household Prophylaxis Trialb | ||
| Placebo N=517 |
Oseltamivir 2 mg/kg bid N=515 |
No Prophylaxisc N=87 |
Prophylaxis with Oseltamivir QDc N=99 |
|
| Vomiting | 48 (9%) | 77 (15%) | 2 (2%) | 10 (10%) |
| Diarrhea | 55 (11%) | 49 (10%) | - | 1 (1%) |
| Otitis media | 58 (11%) | 45 (9%) | 2 (2%) | 2 (2%) |
| Abdominal pain | 20 (4%) | 24 (5%) | - | 3 (3%) |
| Asthma (including aggravated) | 19 (4%) | 18 (3%) | 1 (1%) | 1 (1%) |
| Nausea | 22 (4%) | 17 (3%) | 1 (1%) | 4 (4%) |
| Epistaxis | 13 (3%) | 16 (3%) | - | 1 (1%) |
| Pneumonia | 17 (3%) | 10 (2%) | 2 (2%) | - |
| Ear disorder | 6 (1%) | 9 (2%) | - | - |
| Sinusitis | 13 (3%) | 9 (2%) | - | - |
| Bronchitis | 11 (2%) | 8 (2%) | 2 (2%) | - |
| Conjunctivitis | 2 (<1%) | 5 (1%) | - | - |
| Dermatitis | 10 (2%) | 5 (1%) | - | - |
| Lymphadenopathy | 8 (2%) | 5 (1%) | - | - |
| Tympanic membrane disorder | 6 (1%) | 5 (1%) | - | - |
| a Pooled data from Phase III trials
of TAMIFLU treatment of naturally acquired influenza. b A randomized, open-label study of household transmission in which household contacts received either prophylaxis or no prophylaxis but treatment if they became ill. Only contacts who received prophylaxis or who remained on no prophylaxis are included in this table. c Unit dose = age-based dosing |
||||
| Age | Prophylaxis (10 days) |
| 1-2 years | 30 mg QD |
| 3-5 years | 45 mg QD |
| 6-12 years | 60 mg QD |
Adverse events included in Table 4 are: all events reported in the treatment studies with frequency ≥ 1% in the oseltamivir 75 mg bid group.
The following adverse reactions have been identified during postmarketing use of TAMIFLU. Because these reactions are reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency or establish a causal relationship to TAMIFLU exposure.
Body as a Whole: Swelling of the face or tongue, allergy, anaphylactic/anaphylactoid reactions
Dermatologic: Dermatitis, rash, eczema, urticaria, erythema multiforme, Stevens-Johnson Syndrome, toxic epidermal necrolysis (see PRECAUTIONS)
Digestive: Hepatitis, liver function tests abnormal Cardiac: Arrhythmia
Gastrointestinal disorders: Gastrointestinal bleeding, hemorrhagic colitis
Neurologic: Seizure
Metabolic: Aggravation of diabetes
Psychiatric: Delirium, including symptoms such as altered level of consciousness, confusion, abnormal behavior, delusions, hallucinations, agitation, anxiety, nightmares (see PRECAUTIONS)
The concurrent use of TAMIFLU with live attenuated influenza vaccine (LAIV) intranasal has not been evaluated. However, because of the potential for interference between these products, LAIV should not be administered within 2 weeks before or 48 hours after administration of TAMIFLU, unless medically indicated. The concern about possible interference arises from the potential for antiviral drugs to inhibit replication of live vaccine virus. Trivalent inactivated influenza vaccine can be administered at any time relative to use of TAMIFLU.
Information derived from pharmacology and pharmacokinetic studies of oseltamivir suggests that clinically significant drug interactions are unlikely.
Oseltamivir is extensively converted to oseltamivir carboxylate by esterases, located predominantly in the liver. Drug interactions involving competition for esterases have not been extensively reported in literature. Low protein binding of oseltamivir and oseltamivir carboxylate suggests that the probability of drug displacement interactions is low.
In vitro studies demonstrate that neither oseltamivir nor oseltamivir carboxylate is a good substrate for P450 mixed-function oxidases or for glucuronyl transferases.
Clinically important drug interactions involving competition for renal tubular secretion are unlikely due to the known safety margin for most of these drugs, the elimination characteristics of oseltamivir carboxylate (glomerular filtration and anionic tubular secretion) and the excretion capacity of these pathways. Coadministration of probenecid results in an approximate twofold increase in exposure to oseltamivir carboxylate due to a decrease in active anionic tubular secretion in the kidney. However, due to the safety margin of oseltamivir carboxylate, no dose adjustments are required when coadministering with probenecid.
No pharmacokinetic interactions have been observed when coadministering oseltamivir with amoxicillin, acetaminophen, cimetidine or with antacids (magnesium and aluminum hydroxides and calcium carbonates).
Last updated on RxList: 12/4/2008
There is no evidence for efficacy of TAMIFLU in any illness caused by agents other than influenza viruses Types A and B.
Use of TAMIFLU should not affect the evaluation of individuals for annual influenza vaccination in accordance with guidelines of the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices.
Efficacy of TAMIFLU in patients who begin treatment after 40 hours of symptoms has not been established.
Efficacy of TAMIFLU in the treatment of subjects with chronic cardiac disease and/or respiratory disease has not been established. No difference in the incidence of complications was observed between the treatment and placebo groups in this population. No information is available regarding treatment of influenza in patients with any medical condition sufficiently severe or unstable to be considered at imminent risk of requiring hospitalization.
Safety and efficacy of repeated treatment or prophylaxis courses have not been studied.
Efficacy of TAMIFLU for treatment or prophylaxis has not been established in immunocompromised patients.
Serious bacterial infections may begin with influenza-like symptoms or may coexist with or occur as complications during the course of influenza. TAMIFLU has not been shown to prevent such complications.
The safety and pharmacokinetics in patients with severe hepatic impairment have not been evaluated (see DOSAGE AND ADMINISTRATION).
Dose adjustment is recommended for patients with a serum creatinine clearance < 30 mL/min (see DOSAGE AND ADMINISTRATION).
Rare cases of anaphylaxis and serious skin reactions including toxic epidermal necrolysis, Stevens-Johnson Syndrome, and erythema multiforme have been reported in postmarketing experience with TAMIFLU. TAMIFLU should be stopped and appropriate treatment instituted if an allergic-like reaction occurs or is suspected.
Influenza can be associated with a variety of neurologic and behavioral symptoms which can include events such as hallucinations, delirium, and abnormal behavior, in some cases resulting in fatal outcomes. These events may occur in the setting of encephalitis or encephalopathy but can occur without obvious severe disease.
There have been postmarketing reports (mostly from Japan) of delirium and abnormal behavior leading to injury, and in some cases resulting in fatal outcomes, in patients with influenza who were receiving TAMIFLU. Because these events were reported voluntarily during clinical practice, estimates of frequency cannot be made but they appear to be uncommon based on TAMIFLU usage data. These events were reported primarily among pediatric patients and often had an abrupt onset and rapid resolution. The contribution of TAMIFLU to these events has not been established. Patients with influenza should be closely monitored for signs of abnormal behavior. If neuropsychiatric symptoms occur, the risks and benefits of continuing treatment should be evaluated for each patient.
Patients should be instructed to begin treatment with TAMIFLU as soon as possible from the first appearance of flu symptoms. Similarly, prevention should begin as soon as possible after exposure, at the recommendation of a physician.
Patients should be instructed to take any missed doses as soon as they remember, except if it is near the next scheduled dose (within 2 hours), and then continue to take TAMIFLU at the usual times.
TAMIFLU is not a substitute for a flu vaccination. Patients should continue receiving an annual flu vaccination according to guidelines on immunization practices.
A bottle of 13 g TAMIFLU for Oral Suspension contains approximately 11 g sorbitol. One dose of 75 mg TAMIFLU for Oral Suspension delivers 2 g sorbitol. For patients with hereditary fructose intolerance, this is above the daily maximum limit of sorbitol and may cause dyspepsia and diarrhea.
In 2-year carcinogenicity studies in mice and rats given daily oral doses of the pro-drug oseltamivir phosphate up to 400 mg/kg and 500 mg/kg, respectively, the pro-drug oseltamivir phosphate and the active form oseltamivir carboxylate induced no statistically significant increases in tumors over controls. The mean maximum daily exposures to the prodrug in mice and rats were approximately 130- and 320-fold, respectively, greater than those in humans at the proposed clinical dose based on AUC comparisons. The respective safety margins of the exposures to the active oseltamivir carboxylate were 15 and 50-fold.
Oseltamivir was found to be non-mutagenic in the Ames test and the human lymphocyte chromosome assay with and without enzymatic activation and negative in the mouse micronucleus test. It was found to be positive in a Syrian Hamster Embryo (SHE) cell transformation test. Oseltamivir carboxylate was non-mutagenic in the Ames test and the L5178Y mouse lymphoma assay with and without enzymatic activation and negative in the SHE cell transformation test.
In a fertility and early embryonic development study in rats, doses of oseltamivir at 50, 250, and 1500 mg/kg/day were administered to females for 2 weeks before mating, during mating and until day 6 of pregnancy. Males were dosed for 4 weeks before mating, during and for 2 weeks after mating. There were no effects on fertility, mating performance or early embryonic development at any dose level. The highest dose was approximately 100 times the human systemic exposure (AUC0-24h) of oseltamivir carboxylate.
There are insufficient human data upon which to base an evaluation of risk of TAMIFLU to the pregnant woman or developing fetus. Studies for effects on embryo-fetal development were conducted in rats (50, 250, and 1500 mg/kg/day) and rabbits (50, 150, and 500 mg/kg/day) by the oral route. Relative exposures at these doses were, respectively, 2, 13, and 100 times human exposure in the rat and 4, 8, and 50 times human exposure in the rabbit. Pharmacokinetic studies indicated that fetal exposure was seen in both species. In the rat study, minimal maternal toxicity was reported in the 1500 mg/kg/day group. In the rabbit study, slight and marked maternal toxicities were observed, respectively, in the 150 and 500 mg/kg/day groups. There was a dosedependent increase in the incidence rates of a variety of minor skeletal abnormalities and variants in the exposed offspring in these studies. However, the individual incidence rate of each skeletal abnormality or variant remained within the background rates of occurrence in the species studied.
Because animal reproductive studies may not be predictive of human response and there are no adequate and well-controlled studies in pregnant women, TAMIFLU should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
In lactating rats, oseltamivir and oseltamivir carboxylate are excreted in the milk. It is not known whether oseltamivir or oseltamivir carboxylate is excreted in human milk. TAMIFLU should, therefore, be used only if the potential benefit for the lactating mother justifies the potential risk to the breast-fed infant.
The safety of TAMIFLU has been established in clinical studies which enrolled 741 subjects (374 received placebo and 362 received TAMIFLU). Some seasonal variability was noted in the clinical efficacy outcomes (see Description of Clinical Studies: Studies in Naturally Occurring Influenza: Treatment of Influenza: Geriatric Patients).
Safety and efficacy have been demonstrated in elderly residents of nursing homes who took TAMIFLU for up to 42 days for the prevention of influenza. Many of these individuals had cardiac and/or respiratory disease, and most had received vaccine that season (see Description of Clinical Studies: Studies in Naturally Occurring Influenza: Prophylaxis of Influenza: Adult Patients).
The safety and efficacy of TAMIFLU in pediatric patients younger than 1 year of age have not been studied. TAMIFLU is not indicated for either treatment or prophylaxis of influenza in pediatric patients younger than 1 year of age because of uncertainties regarding the rate of development of the human blood-brain barrier and the unknown clinical significance of non-clinical animal toxicology data for human infants (see Animal Toxicology).
Last updated on RxList: 12/4/2008
At present, there has been no experience with overdose. Single doses of up to 1000 mg of TAMIFLU have been associated with nausea and/or vomiting.
TAMIFLU is contraindicated in patients with known hypersensitivity to any of the components of the product.
Last updated on RxList: 12/4/2008
Oseltamivir phosphate is an ethyl ester prodrug requiring ester hydrolysis for conversion to the active form, oseltamivir carboxylate. Oseltamivir carboxylate is an inhibitor of influenza virus neuraminidase affecting release of viral particles.
The antiviral activity of oseltamivir carboxylate against laboratory strains and clinical isolates of influenza virus was determined in cell culture assays. The concentrations of oseltamivir carboxylate required for inhibition of influenza virus were highly variable depending on the assay method used and the virus tested. The 50% and 90% effective concentrations (EC50 and EC90) were in the range of 0.0008 µM to > 35 µM and 0.004 µM to > 100 µM, respectively (1 µM=0.284 µg/mL). The relationship between the antiviral activity in cell culture and the inhibition of influenza virus replication in humans has not been established.
Influenza A virus isolates with reduced susceptibility to oseltamivir carboxylate have been recovered by serial passage of virus in cell culture in the presence of increasing concentrations of oseltamivir carboxylate. Genetic analysis of these isolates showed that reduced susceptibility to oseltamivir carboxylate is associated with mutations that result in amino acid changes in the viral neuraminidase or viral hemagglutinin or both. Resistance substitutions selected in cell culture in neuraminidase are I222T and H274Y in influenza A N1 and I222T and R292K in influenza A N2. Substitutions E119V, R292K and R305Q have been selected in avian influenza A neuraminidase N9. Substitutions A28T and R124M have been selected in the hemagglutinin of influenza A H3N2 and substitution H154Q in the hemagglutinin of a reassortant human/avian virus H1N9.
In clinical studies in the treatment of naturally acquired infection with influenza virus, 1.3% (4/301) of posttreatment isolates in adult patients and adolescents, and 8.6% (9/105) in pediatric patients aged 1 to 12 years showed emergence of influenza variants with decreased neuraminidase susceptibility in cell culture to oseltamivir carboxylate. Substitutions in influenza A neuraminidase resulting in decreased susceptibility were H274Y in neuraminidase N1 and E119V and R292K in neuraminidase N2. Insufficient information is available to fully characterize the risk of emergence of TAMIFLU resistance in clinical use.
In clinical studies of postexposure and seasonal prophylaxis, determination of resistance by population nucleotide sequence analysis was limited by the low overall incidence rate of influenza infection and prophylactic effect of TAMIFLU.
Cross-resistance between zanamivir-resistant influenza mutants and oseltamivir-resistant influenza mutants has been observed in cell culture. Due to limitations in the assays available to detect drug-induced shifts in virus susceptibility, an estimate of the incidence of oseltamivir resistance and possible cross-resistance to zanamivir in clinical isolates cannot be made. However, two of the three oseltamivir-induced substitutions (E119V, H274Y and R292K) in the viral neuraminidase from clinical isolates occur at the same amino acid residues as two of the three substitutions (E119G/A/D, R152K and R292K) observed in zanamivir-resistant virus.
No influenza vaccine interaction study has been conducted. In studies of naturally acquired and experimental influenza, treatment with TAMIFLU did not impair normal humoral antibody response to infection.
Oseltamivir is readily absorbed from the gastrointestinal tract after oral administration of oseltamivir phosphate and is extensively converted predominantly by hepatic esterases to oseltamivir carboxylate. At least 75% of an oral dose reaches the systemic circulation as oseltamivir carboxylate. Exposure to oseltamivir is less than 5% of the total exposure after oral dosing (see Table 1).
Table 1: Mean (% CV) Pharmacokinetic Parameters of Oseltamivir
and Oseltamivir Carboxylate After a Multiple 75 mg Capsule Twice Daily Oral
Dose (n=20)
| Parameter | Oseltamivir | Oseltamivir Carboxylate |
| Cmax (ng/mL) | 65.2 (26) | 348 (18) |
| AUC0-12h (ng·h/mL) | 112 (25) | 2719 (20) |
Plasma concentrations of oseltamivir carboxylate are proportional to doses up to 500 mg given twice daily (see DOSAGE AND ADMINISTRATION).
Coadministration with food has no significant effect on the peak plasma concentration (551 ng/mL under fasted conditions and 441 ng/mL under fed conditions) and the area under the plasma concentration time curve (6218 ng·h/mL under fasted conditions and 6069 ng·h/mL under fed conditions)of oseltamivir carboxylate.
The volume of distribution (Vss) of oseltamivir carboxylate, following intravenous administration in 24 subjects, ranged between 23 and 26 liters.
The binding of oseltamivir carboxylate to human plasma protein is low (3%). The binding of oseltamivir to human plasma protein is 42%, which is insufficient to cause significant displacement-based drug interactions.
Oseltamivir is extensively converted to oseltamivir carboxylate by esterases located predominantly in the liver. Neither oseltamivir nor oseltamivir carboxylate is a substrate for, or inhibitor of, cytochrome P450 isoforms.
Absorbed oseltamivir is primarily ( > 90%) eliminated by conversion to oseltamivir carboxylate. Plasma concentrations of oseltamivir declined with a half-life of 1 to 3 hours in most subjects after oral administration. Oseltamivir carboxylate is not further metabolized and is eliminated in the urine. Plasma concentrations of oseltamivir carboxylate declined with a half-life of 6 to 10 hours in most subjects after oral administration. Oseltamivir carboxylate is eliminated entirely ( > 99%) by renal excretion. Renal clearance (18.8 L/h) exceeds glomerular filtration rate (7.5 L/h) indicating that tubular secretion occurs, in addition to glomerular filtration. Less than 20% of an oral radiolabeled dose is eliminated in feces.
Administration of 100 mg of oseltamivir phosphate twice daily for 5 days to patients with various degrees of renal impairment showed that exposure to oseltamivir carboxylate is inversely proportional to declining renal function. Oseltamivir carboxylate exposures in patients with normal and abnormal renal function administered various dose regimens of oseltamivir are described in Table 2.
Table 2: Oseltamivir Carboxylate Exposures in Patients With
Normal and Reduced Serum Creatinine Clearance
| Parameter | Normal Renal Function | Impaired Renal Function | ||||||
| 75 mg qd | 75 mg bid | 150 mg bid | Creatinine Clearance <10 mL/min |
Creatinine Clearance >10 and <30 mL/min |
||||
| CAPD | Hemodialysis | 75 mg daily | 75 mg alternate days | 30 mg daily | ||||
| 30 mg weekly | 30 mg alternate HD cycle | |||||||
| Cmax | 259* | 348* | 705* | 766 | 850 | 1638 | 1175 | 655 |
| Cmin | 39* | 138* | 288* | 62 | 48 | 864 | 209 | 346 |
| AUC48 | 7476* | 10876* | 21864* | 17381 | 12429 | 62636 | 21999 | 25054 |
| *Observed values.All other values are predicted. AUC normalized to 48 hours. |
||||||||
In clinical studies oseltamivir carboxylate exposure was not altered in patients with mild or moderate hepatic impairment (see PRECAUTIONS: Hepatic Impairment and DOSAGE AND ADMINISTRATION).
The pharmacokinetics of oseltamivir and oseltamivir carboxylate have been evaluated in a single dose pharmacokinetic study in pediatric patients aged 5 to 16 years (n=18) and in a small number of pediatric patients aged 3 to 12 years (n=5) enrolled in a clinical trial. Younger pediatric patients cleared both the prodrug and the active metabolite faster than adult patients resulting in a lower exposure for a given mg/kg dose. For oseltamivir carboxylate, apparent total clearance decreases linearly with increasing age (up to 12 years). The pharmacokinetics of oseltamivir in pediatric patients over 12 years of age are similar to those in adult patients.
Exposure to oseltamivir carboxylate at steady-state was 25% to 35% higher in geriatric patients (age range 65 to 78 years) compared to young adults given comparable doses of oseltamivir. Half-lives observed in the geriatric patients were similar to those seen in young adults. Based on drug exposure and tolerability, dose adjustments are not required for geriatric patients for either treatment or prophylaxis (see DOSAGE AND ADMINISTRATION: Special Dosage Instructions).
Two phase III placebo-controlled and double-blind clinical trials were conducted: one in the USA and one outside the USA. Patients were eligible for these trials if they had fever > 100ºF, accompanied by at least one respiratory symptom (cough, nasal symptoms or sore throat) and at least one systemic symptom (myalgia, chills/sweats, malaise, fatigue or headache) and influenza virus was known to be circulating in the community. In addition, all patients enrolled in the trials were allowed to take fever-reducing medications.
Of 1355 patients enrolled in these two trials, 849 (63%) patients were influenza-infected (age range 18 to 65 years; median age 34 years; 52% male; 90% Caucasian; 31% smokers). Of the 849 influenza-infected patients, 95% were infected with influenza A, 3% with influenza B, and 2% with influenza of unknown type.
TAMIFLU was started within 40 hours of onset of symptoms. Subjects participating in the trials were required to self-assess the influenza-associated symptoms as "none", "mild", "moderate" or "severe". Time to improvement was calculated from the time of treatment initiation to the time when all symptoms (nasal congestion, sore throat, cough, aches, fatigue, headaches, and chills/sweats) were assessed as "none" or "mild". In both studies, at the recommended dose of TAMIFLU 75 mg twice daily for 5 days, there was a 1.3 day reduction in the median time to improvement in influenza-infected subjects receiving TAMIFLU compared to subjects receiving placebo. Subgroup analyses of these studies by gender showed no differences in the treatment effect of TAMIFLU in men and women.
In the treatment of influenza, no increased efficacy was demonstrated in subjects receiving treatment of 150 mg TAMIFLU twice daily for 5 days.
Three double-blind placebo-controlled treatment trials were conducted in patients ≥ 65 years of age in three consecutive seasons. The enrollment criteria were similar to that of adult trials with the exception of fever being defined as > 97.5 F. Of 741 patients enrolled, 476 (65%) patients were influenza-infected. Of the 476 influenza-infected patients, 95% were infected with influenza type A and 5% with influenza type B.
In the pooled analysis, at the recommended dose of TAMIFLU 75 mg twice daily for 5 days, there was a 1 day reduction in the median time to improvement in influenzainfected subjects receiving TAMIFLU compared to those receiving placebo (p=NS). However, the magnitude of treatment effect varied between studies.
One double-blind placebo-controlled treatment trial was conducted in pediatric patients aged 1 to 12 years (median age 5 years), who had fever ( > 100ºF) plus one respiratory symptom (cough or coryza) when influenza virus was known to be circulating in the community. Of 698 patients enrolled in this trial, 452 (65%) were influenza-infected (50% male; 68% Caucasian). Of the 452 influenza-infected patients, 67% were infected with influenza A and 33% with influenza B.
The primary endpoint in this study was the time to freedom from illness, a composite endpoint which required 4 individual conditions to be met. These were: alleviation of cough, alleviation of coryza, resolution of fever, and parental opinion of a return to normal health and activity. TAMIFLU treatment of 2 mg/kg twice daily, started within 48 hours of onset of symptoms, significantly reduced the total composite time to freedom from illness by 1.5 days compared to placebo. Subgroup analyses of this study by gender showed no differences in the treatment effect of TAMIFLU in males and females.
The efficacy of TAMIFLU in preventing naturally occurring influenza illness has been demonstrated in three seasonal prophylaxis studies and a postexposure prophylaxis study in households. The primary efficacy parameter for all these studies was the incidence of laboratory-confirmed clinical influenza. Laboratory-confirmed clinical influenza was defined as oral temperature ≥ 99.0ºF/37.2ºC plus at least one respiratory symptom (cough, sore throat, nasal congestion) and at least one constitutional symptom (aches and pain, fatigue, headache, chills/sweats), all recorded within 24 hours, plus either a positive virus isolation or a fourfold increase in virus antibody titers from baseline.
In a pooled analysis of two seasonal prophylaxis studies in healthy unvaccinated adults (aged 13 to 65 years), TAMIFLU 75 mg once daily taken for 42 days during a community outbreak reduced the incidence of laboratory-confirmed clinical influenza from 4.8% (25/519) for the placebo group to 1.2% (6/520) for the TAMIFLU group.
In a seasonal prophylaxis study in elderly residents of skilled nursing homes, TAMIFLU 75 mg once daily taken for 42 days reduced the incidence of laboratory-confirmed clinical influenza from 4.4% (12/272) for the placebo group to 0.4% (1/276) for the TAMIFLU group. About 80% of this elderly population were vaccinated, 14% of subjects had chronic airway obstructive disorders, and 43% had cardiac disorders.
In a study of postexposure prophylaxis in household contacts (aged ≥ 13 years) of an index case, TAMIFLU 75 mg once daily administered within 2 days of onset of symptoms in the index case and continued for 7 days reduced the incidence of laboratoryconfirmed clinical influenza from 12% (24/200) in the placebo group to 1% (2/205) for the TAMIFLU group. Index cases did not receive TAMIFLU in the study.
The efficacy of TAMIFLU in preventing naturally occurring influenza illness has been demonstrated in a randomized, open-label, postexposure prophylaxis study in households that included children aged 1 to 12 years, both as index cases and as family contacts. All index cases in this study received treatment. The primary efficacy parameter for this study was the incidence of laboratory-confirmed clinical influenza in the household. Laboratory-confirmed clinical influenza was defined as oral temperature ≥ 100 F/37.8 C plus cough and/or coryza recorded within 48 hours, plus either a positive virus isolation or a fourfold or greater increase in virus antibody titers from baseline or at illness visits. Among household contacts 1 to 12 years of age not already shedding virus at baseline, TAMIFLU for Oral Suspension 30 mg to 60 mg taken once daily for 10 days reduced the incidence of laboratory-confirmed clinical influenza from 17% (18/106) in the group not receiving prophylaxis to 3% (3/95) in the group receiving prophylaxis.
In a 2-week study in unweaned rats, administration of a single dose of 1000 mg/kg oseltamivir phosphate to 7-day-old rats resulted in deaths associated with unusually high exposure to the prodrug. However, at 2000 mg/kg, there were no deaths or other significant effects in 14-day-old unweaned rats. Further follow-up investigations of the unexpected deaths of 7-day-old rats at 1000 mg/kg revealed that the concentrations of the prodrug in the brains were approximately 1500-fold those of the brains of adult rats administered the same oral dose of 1000 mg/kg, and those of the active metabolite were approximately 3-fold higher. Plasma levels of the prodrug were 10-fold higher in 7-dayold rats as compared with adult rats. These observations suggest that the levels of oseltamivir in the brains of rats decrease with increasing age and most likely reflect the maturation stage of the blood-brain barrier. No adverse effects occurred at 500 mg/kg/day administered to 7- to 21-day-old rats. At this dosage, the exposure to prodrug was approximately 800-fold the exposure expected in a 1-year-old child.
Last updated on RxList: 12/4/2008
TAMIFLU
(oseltamivir phosphate)
This leaflet contains important information about TAMIFLU (TAM-ih-flew). Read it well before you begin treatment. This information does not take the place of talking with your healthcare professional about your medical condition or your treatment. This leaflet does not list all the benefits and risks of TAMIFLU. If you have any questions about TAMIFLU, ask your healthcare professional. Only your healthcare professional can determine if TAMIFLU is right for you.
What is TAMIFLU?
TAMIFLU attacks the influenza virus and stops it from spreading inside your body. TAMIFLU treats flu at its source, by attacking the virus that causes the flu, rather than simply masking symptoms.
TAMIFLU is for treating adults and children age 1 and older with the flu whose flu symptoms started within the last day or two. TAMIFLU can also reduce the chance of getting the flu in people age 1 and older who have a higher chance of getting the flu because they spend time with someone who has the flu. TAMIFLU can also reduce the chance of getting the flu if there is a flu outbreak in the community.
What is "Flu"?
"The flu" is an infection caused by the influenza virus. Flu symptoms include fever (usually 100°F to 103°F in adults, and sometimes higher in children) and problems such as cough, sore throat, runny or stuffy nose, headaches, muscle aches, fever, and extreme tiredness. Many people use the term "flu" to mean any combination of these symptoms, such as the common cold, but true influenza infection is often worse and may last longer than a cold.
Flu outbreaks happen about once a year, usually in the winter, when the influenza virus spreads widely in the community. Outside of those outbreaks, only a very tiny number of respiratory infections are caused by the influenza virus.
Should I get a flu shot?
TAMIFLU is not a substitute for a flu vaccination. You should continue to get a flu vaccination every year, according to your healthcare professional's advice.
Who should not take TAMIFLU?
Do not take TAMIFLU if you are allergic to the main ingredient, oseltamivir phosphate, or to any other ingredients of TAMIFLU. Before starting treatment, make sure your healthcare professional knows if you take any other medicines, or are pregnant, planning to become pregnant, or breastfeeding. TAMIFLU is normally not recommended for use during pregnancy or nursing, as the effects on the unborn child or nursing infant are unknown. TAMIFLU is not recommended for use in children younger than 1 year of age.
Tell your healthcare professional if you have any type of kidney disease, heart disease, respiratory disease, or any serious health condition.
TAMIFLU for Oral Suspension contains sorbitol. Sorbitol may cause upset stomach and diarrhea in patients with a family history of fructose intolerance.
How should I take TAMIFLU?
It is important that you begin your treatment with TAMIFLU as soon as possible from the first appearance of your flu symptoms or soon after you are exposed to the flu. If you feel worse or develop new symptoms during treatment with TAMIFLU, or if your flu symptoms do not start to get better, you should contact your healthcare professional.
If you have the flu: Take TAMIFLU twice a day for 5 days, once in the morning and once in the evening. You should complete the entire treatment of 10 doses (capsules or suspension), even if you feel better.
To prevent the flu: If someone in your home has the flu, take TAMIFLU once a day for 10 days or for as long as prescribed. You can take TAMIFLU for up to 6 weeks if you are exposed to the flu because of an outbreak in your community. Follow your healthcare professional's advice on how long to take TAMIFLU.
TAMIFLU has not been studied in children 1 to 12 years of age for preventing flu during an outbreak in your community or for use for more than 10 days.
You can take TAMIFLU with food or without food. There is less chance of stomach upset if you take it with a light snack, milk, or a meal.
If you are taking TAMIFLU for Oral Suspension, your pharmacist will give you a dosing dispenser marked with three possible doses. Follow your healthcare professional's instructions on which dose to take or how to combine them for the proper dose for you. In order to be sure you receive the proper dose, it is important that you use the dispenser provided. Review the instructions below on how to use the dispenser and ask your pharmacist if you have any questions. If you lose or damage the dispenser and cannot use it, contact your healthcare professional or pharmacist for advice on the proper dose.
If TAMIFLU for Oral Suspension is not available, your healthcare provider may instruct you to open TAMIFLU Capsules and mix the contents with sweetened liquids such as regular or sugar-free chocolate syrup. Please follow the dosing instructions below.
If you forget to take your medicine, take the missed dose as soon as you remember, except if it is 2 hours or less before your next dose. Then continue to take TAMIFLU at the usual times. Do not take 2 doses at a time to make up for a missed dose. If you miss several doses, tell your healthcare professional and follow the advice given to you.
What are the possible side effects of TAMIFLU?
The most common side effects of TAMIFLU are nausea and vomiting. These are usually mild to moderate. They usually happen in the first 2 days of treatment. Taking TAMIFLU with food may reduce the chance of getting these side effects.
If you develop an allergic reaction or severe rash, stop taking TAMIFLU and contact your healthcare professional.
People with the flu, particularly children and adolescents, may be at an increased risk of seizures, confusion, or abnormal behavior early during their illness. These events may occur shortly after beginning TAMIFLU or may occur when flu is not treated. These events are uncommon but may result in accidental injury to the patient. Therefore, patients should be observed for signs of unusual behavior and a healthcare professional should be contacted immediately if the patient shows any signs of unusual behavior.
Before taking TAMIFLU, please let your healthcare provider know if you have received nasally administered influenza virus vaccine during the past two weeks.
If you notice any side effects not mentioned in this leaflet, or if you have any concerns about the side effects you get, tell your healthcare professional.
How and where should I store TAMIFLU?
TAMIFLU Capsules should be stored at room temperature, 77°F (25°C) and kept in a dry place. Keep this medication out of reach of children.
TAMIFLU for Oral Suspension should be stored under refrigeration at 36° to 46°F (2° to 8°C). Do not freeze.
General advice about prescription medicines:
Medicines are sometimes prescribed for conditions that are not mentioned in patient information leaflets. Do not use TAMIFLU for a condition for which it was not prescribed. Do not give TAMIFLU to other people, even if they have the same symptoms you have. It may not be right for them.
This leaflet summarizes the most important information about TAMIFLU. If you would like more information, talk with your healthcare professional. You can ask your pharmacist or healthcare professional for information about TAMIFLU that is written for health professionals.
DOSING INSTRUCTIONS FOR PATIENTS:
How Do I Prepare TAMIFLU for Oral Suspension?
Please follow instructions carefully to ensure proper dosing of the oral suspension.
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If Directed by My Healthcare Provider, How Do I Mix the Contents of TAMIFLU Capsules with Sweetened Liquids?
Please follow instructions carefully to ensure proper dosing.
Distributed by: Roche Laboratories Inc., 340 Kingsland Street, Nutley, New Jersey 07110-1199. Licensor: Gilead Sciences, Inc. Foster City, California 94404. Rev. January 2008
Last updated on RxList: 4/30/2009
IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you.
OSELTAMIVIR - ORAL
(oss-el-TAM-eh-veer)
COMMON BRAND NAME(S): Tamiflu
USES: Oseltamivir is used to treat symptoms caused by the flu virus (influenza). It helps make the symptoms (e.g., stuffy nose, cough, sore throat, fever/chills, aches, tiredness) less severe and shortens the recovery time by 1-2 days. This medication is also used to prevent the flu if you have been exposed to someone who already has the flu (e.g., sick household member).
This medication works by stopping the flu virus from growing. It is not a substitute for the flu vaccine. (See Notes)
Oseltamivir should not be used in infants younger than 1 year of age. Consult your doctor or pharmacist for more details.
HOW TO USE: Read the Patient Information Leaflet available from your pharmacist before you start taking this medicine. If you have any questions, consult your doctor or pharmacist.
Take this medication by mouth as directed by your doctor. You may take it with food or milk to minimize stomach upset. Take this medication as soon as flu symptoms appear or as soon as possible after you have been exposed to the flu. Oseltamivir works best if you start taking it within 2 days of either of these events.
If you have the flu, take oseltamivir usually twice a day for 5 days, or as directed by your doctor.
To prevent the flu, take oseltamivir usually once a day for at least 10 days, or as directed by your doctor. Follow your doctor's instructions for how long to take this medicine.
This medication works best when the amount of medicine in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals at the same time(s) every day. Continue to take it for the full time prescribed. Stopping the medication too early may allow the virus to continue to grow, which may result in a relapse of the infection or failure to protect you from the flu.
Inform your doctor if your condition persists or worsens or if new symptoms appear.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
The flu itself or oseltamivir may rarely cause serious mental/mood changes. This may be more likely in children. Tell your doctor immediately of any signs of unusual behavior including confusion, agitation, self-injury.
Seek immediate medical attention if this rare but very serious side effect occurs: chest pain.
A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching, swelling, severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
Contact your doctor for medical advice about side effects. The following numbers do not provide medical advice, but in the US you may report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088. In Canada, you may call Health Canada at 1-866-234-2345.
PRECAUTIONS: Before taking oseltamivir, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease.
This drug may make you dizzy; use caution engaging in activities requiring alertness such as driving or using machinery. Limit alcoholic beverages.
This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.
It is not known if this drug passes into breast milk. Consult your doctor before breast-feeding.
Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use especially of: clopidogrel.
Tell your doctor if you have received flu vaccine in the nose within 2 weeks before treatment with this medication. This medication may lower your protection from flu vaccine given in the nose. Wait at least 2 days after ending treatment with this medication before receiving flu vaccine given in the nose.
This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.
OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly.
NOTES: Do not share this medication with others.
This medication is not a substitute for the flu vaccine. Consult your doctor about the risks and important benefits of receiving a yearly flu shot to lower your chances of getting the flu.
MISSED DOSE: If you miss a dose, use it as soon as you remember. If it is within 2 hours of your next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
STORAGE: Store at room temperature (77 degrees F or 25 degrees C) away from light and moisture. Brief storage between 59-86 degrees F (15-30 degrees C) is permitted. Do not store in the bathroom. Keep all medicines away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Information last revised July 2008 Copyright(c) 2008 First DataBank, Inc.
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