OsmoPrep® (sodium phosphate monobasic monohydrate, USP, and sodium phosphate dibasic anhydrous, USP) is a purgative used to clean the colon prior to colonoscopy. OsmoPrep is manufactured with a highly soluble tablet binder and does not contain microcrystalline cellulose (MCC). OsmoPrep Tablets are oval, white to off-white compressed tablets, debossed with “SLX” on one side of the bisect and “102” on the other side of the bisect. Each OsmoPrep tablet contains 1.102 grams of sodium phosphate monobasic monohydrate, USP and 0.398 grams of sodium phosphate dibasic anhydrous, USP for a total of 1.5 grams of sodium phosphate per tablet. Inert ingredients include polyethylene glycol 8000, NF; and magnesium stearate, NF. OsmoPrep is gluten-free.

The structural and molecular formulae and molecular weights of the active ingredients are shown below:

• Sodium phosphate monobasic monohydrate, USP

Molecular Formula: NaH₂PO₄ •H₂O
Molecular Weight: 137.99

• Sodium phosphate dibasic anhydrous, USP

Molecular Formula: Na₂HPO₄
Molecular Weight: 141.96

OsmoPrep Tablets are for oral administration only.

Last updated on RxList: 9/15/2009

OsmoPrep Tablets are indicated for cleansing of the colon as a preparation for colonoscopy in adults 18 years of age or older.

The recommended dose of OsmoPrep Tablets for colon cleansing for adult patients is 32 tablets (48 grams of sodium phosphate) taken orally with a total of 2 quarts of clear liquids in the following manner:

The evening before the colonoscopy procedure: Take 4 OsmoPrep Tablets with 8 ounces of clear liquids every 15 minutes for a total of 20 tablets.

On the day of the colonoscopy procedure: Starting 3-5 hours before the procedure, take 4 OsmoPrep Tablets with 8 ounces of clear liquids every 15 minutes for a total of 12 tablets.

Patients should be advised of the importance of taking the recommended fluid regimen. It is recommended that patients receiving OsmoPrep be advised to adequately hydrate before, during, and after the use of OsmoPrep.

Patients should not use OsmoPrep for colon cleansing within seven days of previous administration. No additional enema or laxative is required, and patients should be advised NOT to take additional agents, particularly those containing sodium phosphate.

OsmoPrep Tablets are supplied in child-resistant bottles containing 100 tablets. Each tablet contains 1.102 g sodium phosphate monobasic monohydrate, USP and 0.398 g sodium phosphate dibasic anhydrous, USP for a total of 1.5 g of sodium phosphate per tablet.

Each bottle contains two silica desiccant packets, which should not be ingested.

NDC 65649-701-41 (100 tablet bottle)

Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [See USP Controlled Room Temperature]. Discard any unused portion.

Manufactured by: WellSpring Pharmaceutical Canada Corp., Oakville, Ontario Canada L6H 1M5, for: Salix Pharmaceuticals, Inc., Morrisville. NC 27560, Made in Canada. Revised March 2009.

Last updated on RxList: 9/15/2009

Abdominal bloating, abdominal pain, nausea, and vomiting were the most common adverse events reported with the use of OsmoPrep Tablets. Dizziness and headache were reported less frequently. Since diarrhea was considered as a part of the efficacy of OsmoPrep, diarrhea was not defined as an adverse event in the clinical studies. Table 2 shows the most common adverse events associated with the use of 48 grams of OsmoPrep, 60 grams of OsmoPrep, and 60 grams of Visicol in the colon preparation trials (n= 931).

Table 2: Frequency of Adverse Events of Any Severity Occurring in Greater Than 3% of Patients in the OsmoPrep Trials

	OsmoPrep 32 tabs (48 g) N=272	OsmoPrep 40 tabs (60 g) N=265	Visicol 40 tabs (60 g) N=268
Bloating	31%	39%	41%
Nausea	26%	37%	30%
Abdominal Pain	23%	24%	25%
Vomiting	4%	10%	9%

Postmarketing Experience

In addition to adverse events reported from clinical trials, the following adverse events have been identified during post-approval use of OsmoPrep. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to either their seriousness, frequency of reporting or causal connection to OsmoPrep, or a combination of these factors.

General

Hypersensitivity reactions including anaphylaxis, rash, pruritus, urticaria, throat tightness, bronchospasm, dyspnea, pharyngeal edema, dysphagia, paresthesia and swelling of the lips and tongue, and facial swelling.

Cardiovascular

Arrhythmias

Nervous system

Seizures

Renal

Renal impairment, increased blood urea nitrogen (BUN), increased creatinine, acute renal failure, acute phosphate nephropathy, nephrocalcinosis, and renal tubular necrosis.

Drug Abuse And Dependence

Laxatives and purgatives (including OsmoPrep) have the potential for abuse by bulimia nervosa patients who frequently have binge eating and vomiting.

Medications administered in close proximity to OsmoPrep Tablets may not be absorbed from the gastrointestinal tract due to the rapid intestinal peristalsis and watery diarrhea induced by the purgative agent.

Last updated on RxList: 9/15/2009

Administration of sodium phosphate products prior to colonoscopy for colon cleansing has resulted in fatalities due to significant fluid shifts, severe electrolyte abnormalities, and cardiac arrhythmias. These fatalities have been observed in patients with renal insufficiency, in patients with bowel perforation, and in patients who misused or overdosed sodium phosphate products. It is recommended that patients receiving OsmoPrep be advised to adequately hydrate before, during, and after the use of OsmoPrep.

Considerable caution should be advised before OsmoPrep Tablets are used in patients with the following illnesses: severe renal insufficiency (creatinine clearance less than 30 mL/minute), congestive heart failure, ascites, unstable angina, gastric retention, ileus, acute bowel obstruction, pseudo-obstruction of the bowel, severe chronic constipation, bowel perforation, acute colitis, toxic megacolon, gastric bypass or stapling surgery, or hypomotility syndrome.

Consider performing baseline and post-colonoscopy labs (phosphate, calcium, potassium, sodium, creatinine, and BUN) in patients who may be at increased risk for serious adverse events, including those with history of renal insufficiency, history of — or at greater risk of — acute phosphate nephropathy, known or suspected electrolyte disorders, seizures, arrhythmias, cardiomyopathy, prolonged QT, recent history of a MI and those with known or suspected hyperphosphatemia, hypocalcemia, hypokalemia, and hypernatremia. Also if patients develop vomiting and/or signs of dehydration then measure post-colonoscopy labs (phosphate, calcium, potassium, sodium, creatinine, and BUN).

Renal Disease, Acute Phosphate Nephropathy, and Electrolyte Disorders

There have been rare, but serious, reports of renal failure, acute phosphate nephropathy, and nephrocalcinosis in patients who received oral sodium phosphate products (including oral sodium phosphate solutions and tablets) for colon cleansing prior to colonoscopy. These cases often resulted in permanent impairment of renal function and several patients required long-term dialysis. The time to onset is typically within days; however, in some cases, the diagnosis of these events has been delayed up to several months after the ingestion of these products. Patients at increased risk of acute phosphate nephropathy may include patients with the following: hypovolemia, baseline kidney disease, increased age, and patients using medicines that affect renal perfusion or function [such as diuretics, angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers, and possibly nonsteroidal anti-inflammatory drugs (NSAIDs).

Use OsmoPrep with caution in patients with impaired renal function, patients with a history of acute phosphate nephropathy, known or suspected electrolyte disturbances (such as dehydration), or people taking concomitant medications that may affect electrolyte levels (such as diuretics). Patients with electrolyte abnormalities such as hypernatremia, hyperphosphatemia, hypokalemia, or hypocalcemia should have their electrolytes corrected before treatment with OsmoPrep Tablets.

Seizures

There have been rare reports of generalized tonic-clonic seizures and/or loss of consciousness associated with use of sodium phosphate products in patients with no prior history of seizures. The seizure cases were associated with electrolyte abnormalities (e.g., hyponatremia, hypokalemia, hypocalcemia, and hypomagnesemia) and low serum osmolality. The neurologic abnormalities resolved with correction of fluid and electrolyte abnormalities. OsmoPrep should be used with caution in patients with a history of seizures and in patients at higher risk of seizure [patients using concomitant medications that lower the seizure threshold (such as tricyclic antidepressants), patients withdrawing from alcohol or benzodiazepines, or patients with known or suspected hyponatremia].

Cardiac Arrhythmias

There have been rare, but serious, reports of arrhythmias associated with the use of sodium phosphate products. OsmoPrep should be used with caution in patients with higher risk of arrhythmias (patients with a history of cardiomyopathy, patients with prolonged QT, patients with a history of uncontrolled arrhythmias, and patients with a recent history of a myocardial infarction). Pre-dose and post-colonoscopy ECGs should be considered in patients with high risk of serious, cardiac arrhythmias.

General

Patients should be instructed to drink 8 ounces of clear liquids with each 4-tablet dose of OsmoPrep Tablets. Patients should take a total of 2 quarts of clear liquids with OsmoPrep. Inadequate fluid intake, as with any effective purgative, may lead to excessive fluid loss, hypovolemia, and dehydration. Dehydration from purgation may be exacerbated by inadequate oral fluid intake, vomiting, and/or use of diuretics.

Patients should be instructed not to administer additional laxative or purgative agents, particularly additional sodium phosphate-based purgative or enema products.

Prolongation of the QT interval has been observed in some patients who were dosed with sodium phosphate colon preparations. QT prolongation with sodium phosphate tablets has been associated with electrolyte imbalances, such as hypokalemia and hypocalcemia. OsmoPrep Tablets should be used with caution in patients who are taking medications known to prolong the QT interval, since serious complications may occur. Predose and post-colonoscopy ECGs should be considered in patients with known prolonged QT.

Administration of OsmoPrep Tablets may induce colonic mucosal aphthous ulcerations, since this endoscopic finding was observed with other sodium phosphate cathartic preparations. In the OsmoPrep clinical program, aphthous ulcers were observed in 3% of patients who took the 48 gram OsmoPrep dosing regimen. This colonoscopic finding should be considered in patients with known or suspected inflammatory bowel disease.

Because published data suggest that sodium phosphate absorption may be enhanced in patients experiencing an acute exacerbation of chronic inflammatory bowel disease, OsmoPrep Tablets should be used with caution in such patients.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Long-term studies in animals have not been performed to evaluate the carcinogenic potential of OsmoPrep. Studies to evaluate the effect of OsmoPrep on fertility or its mutagenic potential have not been performed.

Pregnancy

Teratogenic Effects

Pregnancy Category C. Animal reproduction studies have not been conducted with OsmoPrep. It is not known whether OsmoPrep can cause fetal harm when administered to a pregnant woman, or can affect reproduction capacity. OsmoPrep Tablets should be given to a pregnant woman only if clearly needed.

Pediatric Use

The safety and efficacy of OsmoPrep Tablets have not been demonstrated in patients less than 18 years of age.

Geriatric Use

In controlled colon preparation trials of OsmoPrep, 228 (24%) of 931 patients were 65 years of age or older. In addition, 49 (5%) of the 931 patients were 75 years of age or older.

Of the 228 geriatric patients in the trials, 134 patients (59%) received at least 48 grams of OsmoPrep. Of the 49 patients 75 years old or older in the trials, 27 (55%) patients received at least 48 grams of OsmoPrep. No overall differences in safety or effectiveness were observed between geriatric patients and younger patients. However, the mean phosphate levels in geriatric patients were greater than the phosphate levels in younger patients after OsmoPrep administration. The mean colonoscopy-day phosphate levels in patients 18-64, 65-74, and ≥ 75 years old who received 48 grams of OsmoPrep in the phase 3 study were 7.0, 7.3, and 8.0 mg/dL, respectively. In addition, in all three sodium phosphate treatment groups, the mean phosphate levels in patients 18-64, 65-74, and ≥ 75 years old in the phase 3 study were 7.4, 7.9, and 8.0 mg/dL, respectively, after sodium phosphate administration. Greater sensitivity of some older individuals cannot be ruled out; therefore, OsmoPrep Tablets should be used with caution in geriatric patients.

Sodium phosphate is known to be substantially excreted by the kidney, and the risk of adverse reactions with sodium phosphate may be greater in patients with impaired renal function. Since geriatric patients are more likely to have impaired renal function, consider performing baseline and post-colonoscopy labs (phosphate, calcium, potassium, sodium, creatinine, and BUN) in these patients (see WARNINGS). It is recommended that patients receiving OsmoPrep be advised to adequately hydrate before, during, and after the use of OsmoPrep.

Last updated on RxList: 9/15/2009

There have been no reported cases of overdosage with OsmoPrep Tablets. Purposeful or accidental ingestion of more than the recommended dosage of OsmoPrep Tablets might be expected to lead to severe electrolyte disturbances, including hyperphosphatemia, hypocalcemia, hypernatremia, or hypokalemia, as well as dehydration and hypovolemia, with attendant signs and symptoms of these disturbances. Certain severe electrolyte disturbances resulting from overdose may lead to cardiac arrhythmias, seizure, renal failure, and death. The patient who has taken an overdosage should be monitored carefully, and treated symptomatically for complications until stable.

OsmoPrep Tablets are contraindicated in patients with biopsy-proven acute phosphate nephropathy.

OsmoPrep Tablets are contraindicated in patients with a known allergy or hypersensitivity to sodium phosphate salts or any of its ingredients.

Last updated on RxList: 9/15/2009

OsmoPrep Tablets, a dosing regimen containing 48 grams of sodium phosphate (32 tablets), induces diarrhea, which effectively cleanses the entire colon. Each administration has a purgative effect for approximately 1 to 3 hours. The primary mode of action is thought to be through the osmotic effect of sodium, causing large amounts of water to be drawn into the colon, promoting evacuation.

Pharmacokinetics

Pharmacokinetic studies with OsmoPrep have not been conducted. However, the following pharmacokinetic study was conducted with Visicol® tablets which contain the same active ingredients (sodium phosphate) as OsmoPrep. In addition, Visicol is administered at a dose that is 25% greater than the OsmoPrep dose.

An open-label pharmacokinetic study of Visicol in healthy volunteers was performed to determine the concentration-time profile of serum inorganic phosphorus levels after Visicol administration. All subjects received the approved Visicol dosing regimen (60 grams of sodium phosphate with a total liquid volume of 3.6 quarts) for colon cleansing. A 30 gram dose (20 tablets given as 3 tablets every 15 minutes with 8 ounces of clear liquids) was given beginning at 6 PM in the evening. The 30 gram dose (20 tablets given as 3 tablets every 15 minutes with 8 ounces of clear liquids) was repeated the following morning beginning at 6 AM.

Twenty-three healthy subjects (mean age 57 years old; 57% male and 43% female; and 65% Hispanic, 30% Caucasian, and 4% African-American) participated in this pharmacokinetic study. The serum phosphorus level rose from a mean (± standard deviation) baseline of 4.0 (± 0.7) mg/dL to 7.7 (± 1.6 mg/dL), at a median of 3 hours after the administration of the first 30-gram dose of sodium phosphate tablets (see Figure 1). The serum phosphorus level rose to a mean of 8.4 (± 1.9) mg/dL, at a median of 4 hours after the administration of the second 30-gram dose of sodium phosphate tablets. The serum phosphorus level remained above baseline for a median of 24 hours after the administration of the initial dose of sodium phosphate tablets (range 16 to 48 hours).

Figure 1 : Mean (± standard deviation) serum phosphorus concentrations

The upper (4.5 mg/dL) and lower (2.6 mg/dL) reference limits for serum phosphate are represented by solid bars.

Special Populations

Renal Insufficiency

The effect of renal dysfunction on the pharmacokinetics of OsmoPrep Tablets has not been studied. Since the inorganic form of phosphate in the circulating plasma is excreted almost entirely by the kidneys, patients with renal disease may have difficulty excreting a large phosphate load. Thus, OsmoPrep Tablets should be used with caution in patients with impaired renal function (see WARNINGS).

Hepatic Insufficiency

OsmoPrep Tablets have not been investigated in patients with hepatic failure.

Geriatric

In a single pharmacokinetic study of sodium phosphate tablets, which included 6 elderly volunteers, plasma half-life increased two-fold in subjects > 70 years of age compared to subjects < 50 years of age (3 subjects and 5 subjects, respectively).

Gender

No difference in serum phosphate AUC values were observed in the single pharmacokinetic study conducted with sodium phosphate tablets in 13 male and 10 female healthy volunteers.

Clinical Studies

The colon cleansing efficacy and safety of OsmoPrep was evaluated in 2 randomized, investigator-blinded, actively controlled, multicenter, U.S. trials in patients scheduled to have an elective colonoscopy. The trials consisted of a dose ranging and a confirmatory phase 3 study.

In the phase 3 trial, patients were randomized into one of the following three sodium phosphate treatment groups: 1) Visicol containing 60 grams of sodium phosphate given in split doses (30 grams in the evening before the colonoscopy and 30 grams on the next day) with at least 3.6 quarts of clear liquids; 2) OsmoPrep containing 60 grams of sodium phosphate given in split doses (30 grams in the evening before the colonoscopy and 30 grams on the next day) with 2.5 quarts of clear liquids; and 3) OsmoPrep containing 48 grams of sodium phosphate (30 grams in the evening before the colonoscopy and 18 grams on the next day) with 2 quarts of clear liquids. Patients were instructed to eat a light breakfast before noon on the day prior to the colonoscopy and then were told to drink only clear liquids after noon on the day prior to the colonoscopy.

The primary efficacy endpoint was the overall colon cleansing response rate in the 4-point Colonic Contents Scale. Response was defined as a rating of “excellent” or “good” on the 4-point scale as determined by the blinded colonoscopist. This phase 3 study was planned to assess the non-inferiority of the two OsmoPrep groups compared to the Visicol group.

The efficacy analysis included 704 adult patients who had an elective colonoscopy. Patients ranged in age from 21 to 89 years old (mean age 56 years old) with 55% female and 45% male patients. Race was distributed as follows: 87% Caucasian, 10% African American, and 3% other race.

The OsmoPrep 60 gram and 48 gram treatment groups demonstrated noninferiority compared to Visicol. See Table 1 for the results.

Table 1: Phase 3 Study – Overall Colon Content Cleansing Response Rates¹

Treatment Arm (grams of sodium phosphate)	No. of tablets taken at 6 PM on the day prior to colonoscopy	No. of tablets taken the next day2	Excellent	Good	Fair	Inadequate	Overall Response Rate (Excellent or Good)
OsmoPrep 32 tabs (48 g) n=236	20	12	76%	19%	3%	2%	95%
OsmoPrep 40 tabs (60 g) n=233	20	20	73%	24%	2%	1%	97%
Visicol 40 tabs (60 g) n=235	20	20	51%	43%	6%	0%	94%
1 Colon-cleansing efficacy was based on response rate to treatment. A patient was considered to be a responder if overall colon cleansing was rated as “excellent” or “good” on a 4-point scale based on the amount of retained “colonic contents”. Excellent was defined as > 90% of mucosa seen, mostly liquid stool, minimal suctioning needed for adequate visualization. Good was defined as > 90% of mucosa seen, mostly liquid stool, significant suctioning needed for adequate visualization. Fair was defined as > 90% of mucosa seen, mixture of liquid and semisolid stool, could be suctioned and/or washed. Inadequate was defined as < 90% of mucosa seen, mixture of semisolid and solid stool which could not be suctioned or washed. 2 On the day of the colonoscopy, study medication was taken 3 to 5 hours before the start of the colonoscopy.

Electrolyte Changes

In the OsmoPrep clinical studies, expected serum electrolyte changes (including phosphate, calcium, potassium, and sodium levels) have been observed in patients taking OsmoPrep. In the overwhelming majority of patients, electrolyte abnormalities were not associated with any adverse events.

In the OsmoPrep phase 3 study, 96%, 96%, and 93% of patients who took 60 grams of Visicol, 60 grams of OsmoPrep, and 48 grams of OsmoPrep, respectively, developed hyperphosphatemia (defined as phosphate level > 5.1 mg/dL) on the day of the colonoscopy. In this study, patients who took 60 grams of Visicol, 60 grams of OsmoPrep, and 48 grams of OsmoPrep had baseline mean phosphate levels of 3.5, 3.5, and 3.6 mg/dL and subsequently developed mean phosphate levels of 7.6, 7.9, and 7.1 mg/dL, respectively, on the day of the colonoscopy.

In the OsmoPrep phase 3 study, 20%, 22%, and 18% of patients who took 60 grams of Visicol, 60 grams of OsmoPrep, and 48 grams of OsmoPrep, respectively, developed hypokalemia (defined as a potassium level < 3.4 mEq/L) on the day of the colonoscopy. In this study, patients who took 60 grams of Visicol, 60 grams of OsmoPrep, and 48 grams of OsmoPrep all had baseline potassium levels of about 4.3 mEq/L and then developed a mean potassium level of 3.7 mEq/L on the day of the colonoscopy.

In the OsmoPrep phase 3 trial, several patients on all three sodium phosphate regimens developed hypocalcemia and hypernatremia that did not require treatment.

Last updated on RxList: 9/15/2009

OsmoPrep®
(AhZ-MO-prep)
(sodium phosphate monobasic monohydrate, USP and sodium phosphate dibasic anhydrous, USP) Tablets

Read the Medication Guide that comes with OsmoPrep before you take it and each time you take it. This Medication Guide does not take the place of talking with your doctor about your medical condition or your treatment. If you have any questions about OsmoPrep, ask your doctor or pharmacist.

What is the most important information I should know about OsmoPrep?

OsmoPrep can cause serious side effects, including:

Serious kidney problems. Rare, but serious kidney problems can happen in people who take medicines made with sodium phosphate, including OsmoPrep, to clean your colon before colonoscopy. These kidney problems can sometimes lead to kidney failure or the need for dialysis for a long time. These problems often happen within a few days, but sometimes may happen several months after taking OsmoPrep.

Conditions that can make you more at risk for having serious kidney problems with OsmoPrep include if you:

• lose too much body fluid (dehydration)
• have slow moving bowels
• have bowels blocked with stool (constipation)
• have severe stomach pain or bloating
• have any disease that causes bowel irritation (colitis)
• have kidney disease
• have heart failure
• take water pills or non-steroidal anti-inflammatory drugs (NSAIDS)

Your age may also affect your risk for having kidney problems with OsmoPrep.

Before you start taking OsmoPrep, tell your doctor if you:

• have kidney problems
• take any medicines for blood pressure, heart disease, or kidney disease

Severe fluid loss. People who take medicines that contain sodium phosphate can have severe loss of body fluid, with severe changes in body salts in the blood, and abnormal heart rhythms. These problems can lead to death.

Tell your doctor if you have any of these symptoms of loss of too much body fluid (dehydration) while taking OsmoPrep:

• vomiting
• dizziness
• urinating less often than normal
• headache

See “What are the possible side effects of OsmoPrep?” for more information about side effects.

What is OsmoPrep?

OsmoPrep is a prescription medicine used in adults 18 years and older, to clean your colon before a colonoscopy. OsmoPrep cleans your colon by causing you to have diarrhea. Cleaning your colon helps your doctor see the inside of your colon more clearly during the colonoscopy.

It is not known if OsmoPrep is safe and works in children under age 18.

Who should not take OsmoPrep?

Do not take OsmoPrep if:

• you have had a kidney biopsy that shows you have kidney problems because of too much phosphate
• you are allergic to sodium phosphate salts or any of the ingredients in OsmoPrep. See the end of this Medication Guide for a list of ingredients in OsmoPrep.

What should I tell my doctor before taking OsmoPrep?

Before taking OsmoPrep, tell your doctor about all of your medical conditions, including if you have:

• any of the medical conditions listed in the section “What is the most important information I should know about OsmoPrep?”
• irritation of the bowel (colitis). OsmoPrep can cause symptoms of irritable bowel disease to flare-up.
• damage to your bowels
• problems with abnormal heart beat
• had a recent heart attack or have other heart problems
• symptoms of too much body fluid loss (dehydration) including vomiting, dizziness, urinating less often than normal, or headache
• had stomach surgery
• a history of seizures
• if you drink alcohol
• are on a low salt diet
• are pregnant. It is not known if OsmoPrep will harm your unborn baby.

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Any medicine that you take close to the time that you take OsmoPrep may not work as well. Especially tell your doctor if you take:

• water pills (diuretics)
• medicines for blood pressure or heart problems
• medicines for kidney damage
• medicines for pain, such as aspirin or a non-steroidal anti-inflammatory drug (NSAID)
• a medicine for seizures
• a laxative for constipation in the last 7 days. You should not take another medicine that contains sodium phosphate while you take OsmoPrep.

Ask your doctor if you are not sure if your medicine is listed above.

Know the medicines you take. Keep a list of your medicines to show your doctor or pharmacist when you get a new prescription.

How should I take OsmoPrep?

• Take OsmoPrep exactly as prescribed by your doctor.
• It is important for you to drink clear liquids before, during, and after taking OsmoPrep. This may help prevent kidney damage. Examples of clear liquids are water, flavored water, lemonade (no pulp), ginger ale or apple juice. Do not drink any liquids colored purple or red.

You must read, understand, and follow these instructions to take OsmoPrep the right way:

On the evening before your colonoscopy, you will take a total of 20 OsmoPrep tablets, as follows:

1. Take 4 OsmoPrep tablets with 8 ounces of clear liquids.
2. Wait 15 minutes.
3. Take 4 more OsmoPrep tablets with 8 ounces of clear liquids.
4. Repeat steps 2 and 3 above, three more times. Make sure you wait 15 minutes after each time.

On the day of your colonoscopy you will take a total of 12 OsmoPrep tablets, starting about 3 to 5 hours before your colonoscopy, as follows:

1. Take 4 OsmoPrep tablets with 8 ounces of clear liquids.
2. Wait 15 minutes.
3. Take 4 more OsmoPrep tablets with 8 ounces of clear liquids.
4. Repeat steps 2 and 3 one more time.

Tell your doctor if you have any of these symptoms while taking OsmoPrep:

• vomiting, dizziness, or if you urinate less often than normal. These may be signs that you have lost too much fluid while taking OsmoPrep.
• trouble drinking clear fluids
• severe stomach cramping, bloating, nausea, or headache

If you take too much OsmoPrep, call your doctor or get medical help right away.

What should I avoid while taking OsmoPrep?

• You should not take other laxatives or enemas made with sodium phosphate, while taking OsmoPrep.
• You should not use OsmoPrep if you have already used it in the last 7 days.

What are the possible side effects of OsmoPrep?

OsmoPrep can cause serious side effects, including:

• See “What is the most important information I should know about OsmoPrep?”
• Seizures or fainting (black-outs). People who take a medicine that contains sodium phosphate, such as OsmoPrep, can have seizures or faint (become unconscious) even if they have not had seizures before. Tell your doctor right away if you have a seizure or faint while taking OsmoPrep.
• Abnormal heart beat (arrhythmias)
• changes in your blood levels of calcium, phosphate, potassium, sodium

The most common side effects of OsmoPrep are:

• bloating
• stomach area (abdominal) pain
• nausea
• vomiting

These are not all the possible side effects of OsmoPrep. For more information, ask your doctor or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

How do I store OsmoPrep?

• Store OsmoPrep at room temperature, between 59ºF to 86°F (15ºC to 30°C).
• Throw away any OsmoPrep that is not needed.
• Keep OsmoPrep and all medicines out of the reach of children.

General information about OsmoPrep

Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use OsmoPrep for a condition for which it was not prescribed. Do not give OsmoPrep to other people, even if they have the same symptoms that you have. It may harm them.

This Medication Guide summarizes the most important information about OsmoPrep. If you would like more information about OsmoPrep, talk with your doctor or pharmacist. You can ask your doctor or pharmacist for information that is written for healthcare professionals. For more information, call 1-866-669-7597 (toll-free) or go to www.Salix.com.

What are the ingredients in OsmoPrep?

Active ingredients: sodium phosphate monobasic monohydrate and sodium phosphate dibasic anhydrous

Inactive ingredients: polyethylene glycol 8000 and magnesium stearate

This Medication Guide has been approved by the U.S. Food and Drug Administration.

Last updated on RxList: 9/15/2009

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.

SODIUM PHOSPHATE MONOBASIC/DIBASIC - ORAL

(SOE-dee-um FOS-fate MAW-no-BAY-sik/dye-BAY-sik)

COMMON BRAND NAME(S): OsmoPrep

USES: This medication is used to clean out the intestines before a colonoscopy. Sodium phosphate is a laxative that works by drawing large amounts of water into the colon, causing you to have watery bowel movements. This cleans out the intestines so that your doctor can clearly view them during your colonoscopy.

HOW TO USE: Take this medication according to the following directions or exactly as directed by your doctor. Take each dose by mouth with at least 8 ounces (240 milliliters) of clear liquid. The evening before your colonoscopy, take 4 tablets every 15 minutes with liquid as directed. Repeat this dose every 15 minutes until you have taken 5 doses (20 tablets). The next day, start taking the medication 3-5 hours before the colonoscopy. Take 4 tablets every 15 minutes with liquids as directed until you have taken 3 doses (12 tablets).

You should not use any other laxative products with sodium phosphate while taking this product or for 7 days after treatment is finished. Doing so may increase your risk for severe side effects.

Dosage is based on your age.

Watery bowel movements usually begin 1 hour after you start to take the tablets. Since the bowel movements can be very large/watery, drink more clear liquids so that you do not lose too much body water (become dehydrated). Consult your doctor or pharmacist for more information.

The watery bowel movements from sodium phosphate may decrease the absorption of your regular medicines. Consult your doctor or pharmacist about how to minimize this effect.

Follow any special dietary restrictions or instructions given by your doctor. A period of not eating is usually recommended, usually starting 12 hours before taking this medication and lasting until after the colonoscopy. Only clear liquids are allowed during this time. Solid food is usually allowed after the colonoscopy.

This medication may cause psychological dependence, especially if you have an eating disorder (e.g., bulimia) and use it for weight loss. This medication should not be used for weight loss due to the possibility for severe side effects. Though very unlikely, abnormal drug-seeking behavior (addiction) is possible with this medication. Do not take this medication more frequently or for a longer time than prescribed. Tell your doctor if you have an eating disorder.

SIDE EFFECTS: Very watery bowel movements are expected with this medication. Nausea, vomiting, stomach/abdominal pain or bloating, dizziness, and headache may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

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.

Tell your doctor immediately if any of these unlikely but serious side effects occur: severe dizziness/lightheadedness, muscle weakness/cramping, dry mouth, fast heartbeat, fast breathing, black/bloody stools.

Tell your doctor immediately if any of these rare but very serious side effects occur: irregular heartbeat, fainting, seizures, decrease in the amount of urine.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: 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: See also How to Use section.

Before taking sodium phosphate, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: chronic heart failure, conditions that cause fluid to build up in the abdomen (e.g., liver failure, low levels of proteins in the blood, cirrhosis), unstable chest pain (angina), problems with emptying the stomach/intestines (e.g., stomach retention, ileus, blockage of the intestines, severe chronic constipation), conditions causing slow movement of the intestines (e.g., hypothyroidism, scleroderma), hole in the intestines (perforation), recent worsening of colitis, low levels of certain minerals in the blood (e.g., calcium, potassium), high levels of certain minerals in the blood (e.g., sodium, phosphate), severe loss of body water (dehydration).

Before using this medication, tell your doctor or pharmacist your medical history, especially of: irregular heartbeat, QT prolongation in the EKG, heart attack or heart surgery within the last 3 months, persistent low blood minerals or dehydration, kidney problems, seizure problem, swallowing problems, narrowing of the swallowing tube (esophagus), conditions that affect body water (e.g., syndrome of inappropriate ADH).

Caution is advised when using this drug in the elderly because they may be more sensitive to the effects of the drug, especially kidney problems, dehydration, and irregular heartbeat.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is not known whether this drug passes into breast milk. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: See also How to Use section.

Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: "water pills" (diuretics such as furosemide and hydrochlorothiazide), ACE inhibitors (e.g., lisinopril, enalapril), angiotensin receptor blockers (e.g., losartan), nonsteroidal anti-inflammatory drugs (e.g., ibuprofen, naproxen).

Sodium phosphate can rarely increase the risk of an abnormal heart rhythm (QTc prolongation in the EKG) from certain medications. These drugs include amiodarone, dofetilide, sotalol, and erythromycin, among others. QTc prolongation can infrequently result in a serious (rarely fatal) irregular heartbeat. Consult your doctor or pharmacist for more details and for instructions on how you may minimize the risk of this effect.

Also report the use of drugs which might increase seizure risk when combined with sodium phosphate such as isoniazid (INH), phenothiazines (e.g., thioridazine), and tricyclic antidepressants (e.g., amitriptyline), among others. Consult your doctor or pharmacist for details.

If you are currently using any of these medications listed above, tell your doctor or pharmacist before starting sodium phosphate.

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. Canada residents can call a provincial poison control center.

NOTES: Do not share this medication with others.

Laboratory and/or medical tests (e.g., blood mineral levels, EKG) may be performed to monitor your progress or check for side effects. Consult your doctor for more details.

MISSED DOSE: This medication should be used as scheduled. If you miss a dose, contact your doctor or pharmacist for instructions. Do not double the dose to catch up.

STORAGE: Store at room temperature at 77 degrees F (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.