UNASYN is an injectable antibacterial combination consisting of the semisynthetic antibiotic ampicillin sodium and the beta-lactamase inhibitor sulbactam sodium for intravenous and intramuscular administration.

Ampicillin sodium is derived from the penicillin nucleus, 6-aminopenicillanic acid. Chemically, it is monosodium (2S, 5R, 6R)-6-[(R)-2-amino-2-phenylacetamido]- 3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate and has a molecular weight of 371.39. Its chemical formula is C₁₆H₁₈N₃NaO₄S. The structural formula is:

Sulbactam sodium is a derivative of the basic penicillin nucleus. Chemically, sulbactam sodium is sodium penicillinate sulfone; sodium (2S, 5R)-3,3-dimethyl-7-oxo-4-thia­ 1-azabicyclo [3.2.0] heptane-2-carboxylate 4,4-dioxide. Its chemical formula is C₈H₁₀NNaO₅S with a molecular weight of 255.22. The structural formula is:

UNASYN, ampicillin sodium/sulbactam sodium parenteral combination, is available as a white to off-white dry powder for reconstitution. UNASYN dry powder is freely soluble in aqueous diluents to yield pale yellow to yellow solutions containing ampicillin sodium and sulbactam sodium equivalent to 250 mg ampicillin per mL and 125 mg sulbactam per mL. The pH of the solutions is between 8.0 and 10.0.

Dilute solutions (up to 30 mg ampicillin and 15 mg sulbactam per mL) are essentially colorless to pale yellow. The pH of dilute solutions remains the same.

UNASYN pharmacy bulk package is a vial containing a sterile preparation of ampicillin sodium and sulbactam sodium for parenteral use that contains many single doses. The Pharmacy Bulk Package is for use in a pharmacy admixture setting; it provides many single doses of UNASYN for addition to suitable parenteral fluids in the preparation of admixtures for intravenous infusion. (See DIRECTIONS FOR PROPER USE OF PHARMACY BULK PACKAGE.)

Last updated on RxList: 5/19/2008

UNASYN is indicated for the treatment of infections due to susceptible strains of the designated microorganisms in the conditions listed below.

Skin and Skin Structure Infections caused by beta-lactamase producing strains of Staphylococcus aureus, Escherichia coli,* Klebsiella spp.* (including K. pneumoniae*), Proteus mirabilis,* Bacteroides fragilis,* Enterobacter spp.,* and Acinetobacter calcoaceticus.*

NOTE: For information on use in pediatric patients see PRECAUTIONS - Pediatric Use and Clinical Studies sections.

Intra-Abdominal Infections caused by beta-lactamase producing strains of Escherichia coli, Klebsiella spp. (including K. pneumoniae*), Bacteroides spp. (including B. fragilis), and Enterobacter spp.*

Gynecological Infections caused by beta-lactamase producing strains of Escherichia coli,* and Bacteroides spp.* (including B. fragilis*).

* Efficacy for this organism in this organ system was studied in fewer than 10 infections.

While UNASYN is indicated only for the conditions listed above, infections caused by ampicillin-susceptible organisms are also amenable to treatment with UNASYN due to its ampicillin content. Therefore, mixed infections caused by ampicillin-susceptible organisms and beta-lactamase producing organisms susceptible to UNASYN should not require the addition of another antibiotic.

Appropriate culture and susceptibility tests should be performed before treatment in order to isolate and identify the organisms causing infection and to determine their susceptibility to UNASYN.

Therapy may be instituted prior to obtaining the results from bacteriological and susceptibility studies, when there is reason to believe the infection may involve any of the beta-lactamase producing organisms listed above in the indicated organ systems. Once the results are known, therapy should be adjusted if appropriate.

To reduce the development of drug-resistant bacteria and maintain effectiveness of UNASYN and other antibacterial drugs, UNASYN should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

UNASYN may be administered by either the IV or the IM routes (following dilution). However, the intent of the pharmacy bulk package is for preparation of solutions for IV infusion only.

For IV administration, the dose can be given by slow intravenous injection over at least 10-15 minutes or can also be delivered, in greater dilutions with 50-100 mL of a compatible diluent as an intravenous infusion over 15-30 minutes.

UNASYN may be administered by deep intramuscular injection. (See Preparation for Intramuscular Injection.)

The recommended adult dosage of UNASYN is 1.5 g (1 g ampicillin as the sodium salt plus 0.5 g sulbactam as the sodium salt) to 3 g (2 g ampicillin as the sodium salt plus 1 g sulbactam as the sodium salt) every six hours. This 1.5 to 3 g range represents the total of ampicillin content plus the sulbactam content of UNASYN, and corresponds to a range of 1 g ampicillin/0.5 g sulbactam to 2 g ampicillin/1 g sulbactam. The total dose of sulbactam should not exceed 4 grams per day.

Pediatric Patients 1 Year of Age or Older: The recommended daily dose of UNASYN in pediatric patients is 300 mg per kg of body weight administered via intravenous infusion in equally divided doses every 6 hours. This 300 mg/kg/day dosage represents the total ampicillin content plus the sulbactam content of UNASYN, and corresponds to 200 mg ampicillin/ 100 mg sulbactam per kg per day. The safety and efficacy of UNASYN administered via intramuscular injection in pediatric patients have not been established. Pediatric patients weighing 40 kg or more should be dosed according to adult recommendations, and the total dose of sulbactam should not exceed 4 grams per day. The course of intravenous therapy should not routinely exceed 14 days. In clinical trials, most children received a course of oral antimicrobials following initial treatment with intravenous UNASYN. (See Clinical Studies section.)

Impaired Renal Function

In patients with impairment of renal function the elimination kinetics of ampicillin and sulbactam are similarly affected, hence the ratio of one to the other will remain constant whatever the renal function.

The dose of UNASYN in such patients should be administered less frequently in accordance with the usual practice for ampicillin and according to the following recommendations:

UNASYN Dosage Guide For Patients With Renal Impairment

Creatinine Clearance (mL/min/1.73m²)	Ampicillin/Sulbactam Half-Life (Hours)	Recommended UNASYN Dosage
≥ 30	1	1.5-3.0 g q 6h-q 8h
15-29	5	1.5-3.0 g q 12h
5-14	9	1.5-3.0 g q 24h

When only serum creatinine is available, the following formula (based on sex, weight, and age of the patient) may be used to convert this value into creatinine clearance. The serum creatinine should represent a steady state of renal function.

Males =	weight (kg) x (140 - age)
	72 x serum creatinine
Females =	0.85 x above value

Compatibility, Reconstitution And Stability

When concomitant therapy with aminoglycosides is indicated, UNASYN and aminoglycosides should be reconstituted and administered separately, due to the in vitro inactivation of aminoglycosides by any of the aminopenicillins.

Directions For Use

General Dissolution Procedures: UNASYN sterile powder for intravenous and intramuscular use may be reconstituted with any of the compatible diluents described in this insert. Solutions should be allowed to stand after dissolution to allow any foaming to dissipate in order to permit visual inspection for complete solubilization.

Preparation for Intravenous Use

UNASYN concentrations between 3 and 45 mg (2 to 30 mg ampicillin/1 to 15 mg sulbactam/mL) are recommended for intravenous use.

Directions For Proper Use of Pharmacy Bulk Package

The 15 gram vial may be reconstituted with either 92 mL Sterile Water for Injection or 0.9% Sodium Chloride Injection. The diluent should be added in two separate aliquots in a suitable work area, such as a laminar flow hood. Add 50 mL of solution, shake to dissolve. Then add an additional 42 mL and shake. The solution should be allowed to stand after dissolution to allow any foaming to dissipate in order to permit visual inspection for complete solubilization. The resultant solution will have a final concentration of approximately 100 mg/mL ampicillin and 50 mg/mL sulbactam. The closure may be penetrated only one time after reconstitution, if needed, using a suitable sterile transfer device or dispensing set that allows for measured dispensing of the contents.

After reconstitution, use within two hours if stored at room temperature, or within four hours if stored under refrigeration.

Reconstituted Bulk Solution Should Not be Used For Direct Infusion

If the reconstituted bulk solution is stored for less than one hour at room temperature (20 C/68 F) prior to further dilution, the use periods indicated in Table A apply for the diluted solutions.

If the bulk solution is stored for one to two hours at room temperature (20 C/68 F) and then diluted with Sterile Water for Injection or 0.9% Sodium Chloride Injection to the following concentrations, the use periods indicated in Table B apply.

Any unused portions of solution that remain after the indicated time periods should be discarded.

Table A

Diluent	Maximum Concentration (mg/mL) UNASYN (Ampicillin/Sulbactam)	Use Periods
Sterile Water for Injection	45 (30/15)	8 hrs @ 21°C
	45 (30/15)	48 hrs @ 4°C
	30 (20/10)	72 hrs @ 4°C
0.9% Sodium Chloride Injection	45 (30/15)	8 hrs @ 21°C
	45 (30/15)	48 hrs @ 4°C
	30 (20/10)	72 hrs @ 4 C
5% Dextrose Injection	30 (20/10)	2 hrs @ 21°C
	30 (20/10)	4 hrs @ 4°C
	3 (2/1)	2 hrs @ 21°C
Lactated Ringer's Injection	45 (30/15)	8 hrs@21°C
	45 (30/15)	24 hrs @ 4°C
M/6 Sodium Lactate Injection	45 (30/15)	8 hrs @ 21 °C
	45 (30/15)	12 hrs @ 4 C
5% Dextrose in 0.45% Saline	3 (2/1)	4 hrs @ 21°C
	15 (10/5)	4 hrs @ 4°C
10% Invert Sugar	3 (2/1)	4 hrs @ 21°C
	30 (20/10)	3 hrs @ 4°C

Table B

IV Solution	Maximum Concentration (mg/mL) UNASYN (Ampicillin/Sulbactam)	Use Period
Sterile Water for Injection,	45 (30/15)	4 hrs @ 21°C
USP	45 (30/15)	24 hrs @ 4°C
0.9% Sodium Chloride Injection,	45 (30/15)	4 hrs @ 21°C
USP	45 (30/15)	24 hrs @ 4°C

UNASYN (ampicillin sodium/sulbactam sodium), a sterile off-white dry powder, is available in Pharmacy Bulk Package containing ampicillin sodium and sulbactam sodium equivalent to 10 g ampicillin and 5 g sulbactam x 1 (NDC 0049-0024-28).

UNASYN sterile powder is to be stored at or below 30 C (86 F) prior to reconstitution.

Other Size Packages Available

UNASYN® is also supplied in glass vial and piggy back bottles in the following package sizes:

Vials containing 1.5 g (NDC 0049-0013-83) equivalent of UNASYN (1 g ampicillin as the sodium salt plus 0.5 g sulbactam as the sodium salt)

Vials containing 3 g (NDC 0049-0014-83) equivalent of UNASYN (2 g ampicillin as the sodium salt plus 1 g sulbactam as the sodium salt)

Bottles containing 1.5 g (NDC 0049-0022-83) equivalent of UNASYN (1 g ampicillin as the sodium salt plus 0.5 g sulbactam as the sodium salt)

Bottles containing 3 g (NDC 0049-0023-83) equivalent of UNASYN (2 g ampicillin as the sodium salt plus 1 g sulbactam as the sodium salt)

ADD-Vantage® vials containing 1.5 g (NDC 0049-0031-83) equivalent of UNASYN (1g ampicillin as the sodium salt plus 0.5 g sulbactam as the sodium salt) are distributed by Pfizer Inc.

ADD-Vantage® vials containing 3 g (N DC 0049-0032-83) equivalent of UNASYN (2g ampicillin as the sodium salt plus 1 g sulbactam as the sodium salt) are distributed by Pfizer Inc.

The 1.5 g UNASYN ADD-Vantage® vials are only to be used with Abbott Vantage® Flexible Diluent Contai ner containing 0.9% Sodium Chloride Injection, USP, 50 mL, 100 mL, or 250 mL sizes.

The 3 g UNASYN ADD-Vantage® vials are only to be used with Abbott ADD Vantage® Flexible Diluent Cont ainer containing 0.9% Sodium Chloride Injection, USP, 100 mL or 250 mL sizes.

Revised April 2007. Distributed by: Roerig, Division of Pfizer Inc., Ny, NY 10017. FDA revision date: 4/14/2008.

Last updated on RxList: 5/19/2008

Adult Patients: UNASYN is generally well tolerated. The following adverse reactions have been reported.

Local Adverse Reactions

Pain at IM injection site - 16%
Pain at IV injection site - 3%
Thrombophlebitis - 3%

Systemic Adverse Reactions

The most frequently reported adverse reactions were diarrhea in 3% of the patients and rash in less than 2% of the patients.

Additional systemic reactions reported in less than 1% of the patients were: itching, nausea, vomiting, candidiasis, fatigue, malaise, headache, chest pain, flatulence, abdominal distension, glossitis, urine retention, dysuria, edema, facial swelling, erythema, chills, tightness in throat, substernal pain, epistaxis and mucosal bleeding.

Pediatric Patients: Available safety data for pediatric patients treated with UNASYN demonstrate a similar adverse events profile to those observed in adult patients. Additionally, atypical lymphocytosis has been observed in one pediatric patient receiving UNASYN.

Adverse Laboratory Changes

Adverse laboratory changes without regard to drug relationship that were reported during clinical trials were:

Hepatic: Increased AST (SGOT), ALT (SGPT), alkaline phosphatase, and LDH.

Hematologic: Decreased hemoglobin, hematocrit, RBC, WBC, neutrophils, lymphocytes, platelets and increased lymphocytes, monocytes, basophils, eosinophils, and platelets.

Blood Chemistry: Decreased serum albumin and total proteins.

Renal: Increased BUN and creatinine.

Urinalysis: Presence of RBC's and hyaline casts

The following adverse reactions have been reported with ampicillin-class antibiotics and can also occur with UNASYN.

Gastrointestinal: Gastritis, stomatitis, black “hairy” tongue and enterocolitis. Onset of pseudomembranous colitis symptoms may occur during or after antibiotic treatment. (See WARNINGS.)

Hypersensitivity Reactions: Urticaria, erythema multiforme, and an occasional case of exfoliative dermatitis have been reported. These reactions may be controlled with antihistamines and, if necessary, systemic corticosteroids. Whenever such reactions occur, the drug should be discontinued, unless the opinion of the physician dictates otherwise. Serious and occasional fatal hypersensitivity (anaphylactic) reactions can occur with a penicillin. (See WARNINGS.)

Hematologic: In addition to the adverse laboratory changes listed above for UNASYN, agranulocytosis has been reported during therapy with penicillins. All of these reactions are usually reversible on discontinuation of therapy and are believed to be hypersensitivity phenomena. Some individuals have developed positive direct Coombs Tests during treatment with UNASYN, as with other beta-lactam antibiotics.

Probenecid decreases the renal tubular secretion of ampicillin and sulbactam. Concurrent use of probenecid with UNASYN may result in increased and prolonged blood levels of ampicillin and sulbactam. The concurrent administration of allopurinol and ampicillin increases substantially the incidence of rashes in patients receiving both drugs as compared to patients receiving ampicillin alone. It is not known whether this potentiation of ampicillin rashes is due to allopurinol or the hyperuricemia present in these patients. There are no data with UNASYN and allopurinol administered concurrently. UNASYN and aminoglycosides should not be reconstituted together due to the in vitro inactivation of aminoglycosides by the ampicillin component of UNASYN.

Drug/Laboratory Test Interactions: Administration of UNASYN will result in high urine concentration of ampicillin. High urine concentrations of ampicillin may result in false positive reactions when testing for the presence of glucose in urine using Clinitest™, Benedict's Solution or Fehling's Solution. It is recommended that glucose tests based on enzymatic glucose oxidase reactions (such as Clinistix™ or Testape™) be used. Following administration of ampicillin to pregnant women, a transient decrease in plasma concentration of total conjugated estriol, estriol-glucuronide, conjugated estrone and estradiol has been noted. This effect may also occur with UNASYN.

Last updated on RxList: 5/19/2008

SERIOUS AND OCCASIONALLY FATAL HYPERSENSITIVITY (ANAPHYLACTIC) REACTIONS HAVE BEEN REPORTED IN PATIENTS ON PENICILLIN THERAPY. THESE REACTIONS ARE MORE APT TO OCCUR IN INDIVIDUALS WITH A HISTORY OF PENICILLIN HYPERSENSITIVITY AND/OR HYPERSENSITIVITY REACTIONS TO MULTIPLE ALLERGENS. THERE HAVE BEEN REPORTS OF INDIVIDUALS WITH A HISTORY OF PENICILLIN HYPERSENSITIVITY WHO HAVE EXPERIENCED SEVERE REACTIONS WHEN TREATED WITH CEPHALOSPORINS. BEFORE THERAPY WITH A PENICILLIN, CAREFUL INQUIRY SHOULD BE MADE CONCERNING PREVIOUS HYPERSENSITIVITY REACTIONS TO PENICILLINS, CEPHALOSPORINS, AND OTHER ALLERGENS. IF AN ALLERGIC REACTION OCCURS, UNASYN SHOULD BE DISCONTINUED AND THE APPROPRIATE THERAPY INSTITUTED.

SERIOUS ANAPHYLACTOID REACTIONS REQUIRE IMMEDIATE EMERGENCY TREATMENT WITH EPINEPHRINE. OXYGEN, INTRAVENOUS STEROIDS, AND AIRWAY MANAGEMENT, INCLUDING INTUBATION, SHOULD ALSO BE ADMINISTERED AS INDICATED.

Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including UNASYN, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile.

C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents.

If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated.

General: A high percentage of patients with mononucleosis who receive ampicillin develop a skin rash. Thus, ampicillin class antibiotics should not be administered to patients with mononucleosis. In patients treated with UNASYN the possibility of superinfections with mycotic or bacterial pathogens should be kept in mind during therapy. If superinfections occur (usually involving Pseudomonas or Candida), the drug should be discontinued and/or appropriate therapy instituted.

Prescribing UNASYN in the absence of proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

Information for Patients: Patients should be counseled that antibacterial drugs including UNASYN should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When UNASYN is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by UNASYN or other antibacterial drugs in the future.

Diarrhea is a common problem caused by antibiotics which usually ends when the antibiotic is discontinued. Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibiotic. If this occurs, patients should contact their physician as soon as possible.

Carcinogenesis, Mutagenesis, Impairment of Fertility: Long-term studies in animals have not been performed to evaluate carcinogenic or mutagenic potential.

Pregnancy

Pregnancy Category B:Reproduction studies have been performed in mice, rats, and rabbits at doses up to ten (10) times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to UNASYN. There are, however, no adequate and well controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. (See- Drug/Laboratory Test Interactions.)

Labor and Delivery: Studies in guinea pigs have shown that intravenous administration of ampicillin decreased the uterine tone, frequency of contractions, height of contractions, and duration of contractions. However, it is not known whether the use of UNASYN in humans during labor or delivery has immediate or delayed adverse effects on the fetus, prolongs the duration of labor, or increases the likelihood that forceps delivery or other obstetrical intervention or resuscitation of the newborn will be necessary.

Nursing Mothers: Low concentrations of ampicillin and sulbactam are excreted in the milk; therefore, caution should be exercised when UNASYN is administered to a nursing woman.

Pediatric Use: The safety and effectiveness of UNASYN have been established for pediatric patients one year of age and older for skin and skin structure infections as approved in adults. Use of UNASYN in pediatric patients is supported by evidence from adequate and well-controlled studies in adults with additional data from pediatric pharmacokinetic studies, a controlled clinical trial conducted in pediatric patients and post-marketing adverse events surveillance. (See CLINICAL PHARMACOLOGY, INDICATIONS AND USAGE, ADVERSE REACTIONS, DOSAGE AND ADMINISTRATION, Clinical Studies sections.)

The safety and effectiveness of UNASYN have not been established for pediatric patients for intra- abdominal infections.

Last updated on RxList: 5/19/2008

Neurological adverse reactions, including convulsions, may occur with the attainment of high CSF levels of beta-lactams. Ampicillin may be removed from circulation by hemodialysis. The molecular weight, degree of protein binding and pharmacokinetics profile of sulbactam suggest that this compound may also be removed by hemodialysis.

The use of UNASYN is contraindicated in individuals with a history of hypersensitivity reactions to any of the penicillins.

Last updated on RxList: 5/19/2008

General: Immediately after completion of a 15-minute intravenous infusion of UNASYN, peak serum concentrations of ampicillin and sulbactam are attained. Ampicillin serum levels are similar to those produced by the administration of equivalent amounts of ampicillin alone. Peak ampicillin serum levels ranging from 109 to 150 mcg/mL are attained after administration of 2000 mg of ampicillin plus 1000 mg sulbactam and 40 to 71 mcg/mL after administration of 1000 mg ampicillin plus 500 mg sulbactam. The corresponding mean peak serum levels for sulbactam range from 48 to 88 mcg/mL and 21 to 40 mcg/mL, respectively. After an intramuscular injection of 1000 mg ampicillin plus 500 mg sulbactam, peak ampicillin serum levels ranging from 8 to 37 mcg/mL and peak sulbactam serum levels ranging from 6 to 24 mcg/mL are attained.

The mean serum half-life of both drugs is approximately 1 hour in healthy volunteers.

Approximately 75 to 85% of both ampicillin and sulbactam are excreted unchanged in the urine during the first 8 hours after administration of UNASYN to individuals with normal renal function. Somewhat higher and more prolonged serum levels of ampicillin and sulbactam can be achieved with the concurrent administration of probenecid.

In patients with impaired renal function the elimination kinetics of ampicillin and sulbactam are similarly affected, hence the ratio of one to the other will remain constant whatever the renal function. The dose of UNASYN in such patients should be administered less frequently in accordance with the usual practice for ampicillin (see DOSAGE AND ADMINISTRATION).

Ampicillin has been found to be approximately 28% reversibly bound to human serum protein and sulbactam approximately 38% reversibly bound.

The following average levels of ampicillin and sulbactam were measured in the tissues and fluids listed:

TABLE A: Concentration of UNASYN in Various Body Tissues and Fluids

Fluid or Tissue	Dose (grams) Ampicillin/Sulbactam	Concentration (mcg/mL or mcg/g) Ampicillin/Sulbactam
Peritoneal Fluid	0.5/0.5 IV	7/14
Blister Fluid (Cantharides)	0.5/0.5 IV	8/20
Tissue Fluid	1/0.5 IV	8/4
Intestinal Mucosa	0.5/0.5 IV	11/18
Appendix	2/1 IV	3/40

Penetration of both ampicillin and sulbactam into cerebrospinal fluid in the presence of inflamed meninges has been demonstrated after IV administration of UNASYN.

The pharmacokinetics of ampicillin and sulbactam in pediatric patients receiving UNASYN are similar to those observed in adults. Immediately after a 15-minute infusion of 50 to 75 mg UNASYN/kg body weight, peak serum and plasma concentrations of 82 to 446 mcg ampicillin/mL and 44 to 203 mcg sulbactam/mL were obtained. Mean half-life values were approximately 1 hour.

Microbiology

Ampicillin is similar to benzyl penicillin in its bactericidal action against susceptible organisms during the stage of active multiplication. It acts through the inhibition of cell wall mucopeptide biosynthesis. Ampicillin has a broad spectrum of bactericidal activity against many gram-positive and gram-negative aerobic and anaerobic bacteria. (Ampicillin is, however, degraded by beta-lactamases and therefore the spectrum of activity does not normally include organisms which produce these enzymes.)

A wide range of beta-lactamases found in microorganisms resistant to penicillins and cephalosporins have been shown in biochemical studies with cell free bacterial systems to be irreversibly inhibited by sulbactam. Although sulbactam alone possesses little useful antibacterial activity except against the Neisseriaceae, whole organism studies have shown that sulbactam restores ampicillin activity against beta-lactamase producing strains. In particular, sulbactam has good inhibitory activity against the clinically important plasmid mediated beta-lactamases most frequently responsible for transferred drug resistance. Sulbactam has no effect on the activity of ampicillin against ampicillin susceptible strains.

The presence of sulbactam in the UNASYN formulation effectively extends the antibiotic spectrum of ampicillin to include many bacteria normally resistant to it and to other beta-lactam antibiotics. Thus, UNASYN possesses the properties of a broad-spectrum antibiotic and a beta-lactamase inhibitor.

While in vitro studies have demonstrated the susceptibility of most strains of the following organisms, clinical efficacy for infections other than those included in the indications section has not been documented.

Gram-Positive Bacteria: Staphylococcus aureus (beta-lactamase and non-beta-lactamase producing), Staphylococcus epidermidis (beta-lactamase and non-beta-lactamase producing), Staphylococcus saprophyticus (beta-lactamase and non-beta-lactamase producing), Streptococcus faecalis^† (Enterococcus), Streptococcus pneumoniae^† (formerly D. pneumoniae), Streptococcus pyogenes^† , Streptococcus viridans^† .

Gram-Negative Bacteria: Hemophilus influenzae (beta-lactamase and non-beta-lactamase producing), Moraxella (Branhamella) catarrhalis (beta-lactamase and non-beta-lactamase producing), Escherichia coli (beta-lactamase and non-beta-lactamase producing), Klebsiella species (all known strains are beta-lactamase producing), Proteus mirabilis (beta-lactamase and non-beta-lactamase producing),

Proteus vulgaris, Providencia rettgeri, Providencia stuartii, Morganella morganii, and Neisseria gonorrhoeae (beta-lactamase and non-beta-lactamase producing).

Anaerobes: Clostridium species^† , Peptococcus species^† , Peptostreptococcus species, Bacteroides species, including B. fragilis.

^† These are not beta-lactamase producing strains and, therefore, are susceptible to ampicillin alone.

Susceptibility Testing

Diffusion Technique: For the Kirby-Bauer method of susceptibility testing, a 20 mcg (10 mcg ampicillin + 10 mcg sulbactam) diffusion disk should be used. The method is one outlined in the NCCLS publication M2-A4.¹ With this procedure, a report from the laboratory of “Susceptible” indicates that the infecting organism is likely to respond to UNASYN therapy and a report of “Resistant” indicates that the infecting organism is not likely to respond to therapy. An “Intermediate” susceptibility report suggests that the infecting organism would be susceptible to UNASYN if a higher dosage is used or if the infection is confined to tissues or fluids (e.g., urine) in which high antibiotic levels are attained.

Dilution Techniques: Broth or agar dilution methods may be used to determine the minimal inhibitory concentration (MIC) value for susceptibility of bacterial isolates to ampicillin/ sulbactam. The method used is one outlined in the NCCLS publication M7-A2.² Tubes should be inoculated to contain 10⁵ to 10⁶ organisms/mL or plates “spotted” with 10⁴ organisms.

The recommended dilution method employs a constant ampicillin/sulbactam ratio of 2:1 in all tubes with increasing concentrations of ampicillin. MIC's the presence of sulbactam at a constant 2 parts ampicillin to 1 part sulbactam.

Recommended ampicillin/sulbactam, Susceptibility Ranges^1,2,3

	Resistant	Intermediate	Susceptible
Gram(-) and Staphylococcus
Bauer/Kirby	≤ 11 mm	12-13 mm	≥ 14 mm
Zone Sizes MIC (mcg of ampicillin/mL)	≥ 32	16	≤ 8
Hemophilus influenzae
Bauer/Kirby	≤ 19	-	≥ 20
Zone Sizes MIC (mcg of ampicillin/mL)	≥ 4	-	≤ 2
1The non-beta-lactamase producing organisms which are normally susceptible to ampicillin, such as Streptococci, will have similar zone sizes as for ampicillin disks. 2Staphylococci resistant to methicillin, oxacillin, or nafcillin must be considered resistant to UNASYN. 3The quality control cultures should have the following assigned daily ranges for ampicillin/sulbactam:

		Disks	Mode MIC (mcg/mL ampicillin/mcg/ mL sulbactam)
E. coli	(ATCC 25922)	20-24 mm	2/1
S. aureus	(ATCC 25923)	29-37 mm	0.12/0.06
E. coli	(ATCC 35218)	13-19 mm	8/4

Clinical Studies

Skin and Skin Structure Infections in Pediatric Patients: Data from a controlled clinical trial conducted in pediatric patients provided evidence supporting the safety and efficacy of UNASYN for the treatment of skin and skin structure infections. Of 99 pediatric patients evaluable for clinical efficacy, 60 patients received a regimen containing intravenous UNASYN, and 39 patients received a regimen containing intravenous cefuroxime. This trial demonstrated similar outcomes (assessed at an appropriate interval after discontinuation of all antimicrobial therapy) for UNASYN- and cefuroxime­ treated patients:

Therapeutic Regimen	Clinical Success	Clinical Failure
UNASYN	51/60 (85%)	9/60 (15%)
Cefuroxime	34/39 (87%)	5/39 (13%)

Most patients received a course of oral antimicrobials following initial treatment with intravenous administration of parenteral antimicrobials. The study protocol required that the following three criteria be met prior to transition from intravenous to oral antimicrobial therapy: 1) receipt of a minimum of 72 hours of intravenous therapy; 2) no documented fever for prior 24 hours; and 3) improvement or resolution of the signs and symptoms of infection.

The choice of oral antimicrobial agent used in this trial was determined by susceptibility testing of the original pathogen, if isolated, to oral agents available. The course of oral antimicrobial therapy should not routinely exceed 14 days.

Animal Pharmacology: While reversible glycogenosis was observed in laboratory animals, this phenomenon was dose- and time-dependent and is not expected to develop at the therapeutic doses and corresponding plasma levels attained during the relatively short periods of combined ampicillin/sulbactam therapy in man.

REFERENCES

1. National Committee for Clinical Laboratory Standards, Performance Standards for Antimicrobial Disk Susceptibility Tests-Fourth Edition. Approved Standard NCCLS Document M2-A4, Vol. 10, No. 7 NCCLS, Villanova, PA, April 1990.

2. National Committee for Clinical Laboratory Standards, Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically, Second Edition. Approved Standard NCCLS Document M7-A2, Vol. 10, No. 8 NCCLS, Villanova, PA, April 1990.

Last updated on RxList: 5/19/2008

No information provided. Please refer to the WARNINGS and PRECAUTIONS sections.

Last updated on RxList: 5/19/2008

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.

AMPICILLIN/SULBACTAM - INJECTION

(AM-pi-SIL-in/sul-BAK-tam)

COMMON BRAND NAME(S): Unasyn

USES: This combination medication is used to treat a wide variety of bacterial infections. It is known as a penicillin-type antibiotic. It works by stopping the growth of bacteria.

This antibiotic treats only bacterial infections. It will not work for viral infections (e.g., common cold, flu). Unnecessary use or misuse of any antibiotic can lead to its decreased effectiveness.

HOW TO USE: This medication is given by injection by a health care professional. Follow all instructions for preparation and use of this product. Before using this product, check it visually for particles or discoloration. If either is present, do not use the liquid. If you have questions about the use of this medication, consult the pharmacist.

This medication is usually given every 6 hours or as directed by your doctor.

The dosage is based on your medical condition and response to therapy. For children, the dosage is also based on weight.

Antibiotics work best when the amount of medicine in your body is kept at a constant level. Therefore, use this drug at evenly spaced intervals.

Continue to use this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.

Inform your doctor if your condition persists or worsens.

SIDE EFFECTS: Nausea, vomiting, or diarrhea may occur. If this medication is injected into a muscle, pain at the injection site may occur. If any of these effects persist or worsen, notify 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: pain/swelling at injection site (if this drug is injected into a vein), chest pain, difficult/painful urination.

Tell your doctor immediately if any of these rare but very serious side effects occur: easy bruising/bleeding, dark urine, yellowing eyes/skin, severe abdominal/stomach pain, new signs of infection (e.g., fever, persistent sore throat), change in the amount of urine.

This medication may rarely cause a severe intestinal condition (pseudomembranous colitis) due to a type of resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Do not use anti-diarrhea products or narcotic pain medications if you have any of the following symptoms because these products may make them worse. Tell your doctor immediately if you develop persistent diarrhea, abdominal or stomach pain/cramping, or blood/mucus in your stool.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

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.

Ampicillin can commonly cause a mild rash that is usually not serious. However, you may not be able to tell it apart from a rare rash that could be a sign of a severe allergic reaction. Therefore, seek immediate medical attention if you develop any rash.

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 using this medication, tell your doctor or pharmacist if you are allergic to it; or to penicillin or cephalosporin antibiotics; or if you have any other allergies.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: viral infections (e.g., infectious mononucleosis), kidney disease.

This medication contains sodium. Consult your doctor or pharmacist if you are on a salt-restricted diet or if you have a condition that could be worsened by an increase in salt intake (e.g., congestive heart failure).

Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, elderly people may be at greater risk for side effects while using this drug.

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

This medication passes into breast milk. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: 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: allopurinol, "blood thinners" (e.g., warfarin), live bacterial vaccines, methotrexate, probenecid, tetracyclines.

Give aminoglycosides (e.g., gentamicin) separately from this medication. Do not mix together in the same IV fluid.

This medication may decrease the effectiveness of combination-type hormonal birth control (e.g., pills, patch). This can result in pregnancy. Ask your doctor or pharmacist for details. Discuss whether you should use additional reliable birth control methods while you are using hormonal birth control along with ampicillin/sulbactam.

This medication may interfere with certain laboratory tests (including certain urine glucose tests), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

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. Symptoms of overdose may include: seizures.

NOTES: This medication has been prescribed for your current condition only. Do not use it later for another infection unless told to do so by your doctor. A different medication may be necessary in that case.

Laboratory and/or medical tests (e.g., kidney function, complete blood count) may be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

MISSED DOSE: If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE: This medication must be stored properly. Review storage instructions with the pharmacist. Check the expiration date before using. Store the vial at room temperature below 86 degrees F (30 degrees C) away from light and moisture. 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.