DrugindexOnline^{2nd edition}

Pronouncation: (am-pih-SILL-in SO-dee-uhm/sull-BAK-tam SO-dee-uhm)
Class: Aminopenicillin

Trade Names:
Unasyn
- Powder for injection 1.5 g (1 g ampicillin sodium per 0.5 g sulbactam sodium)
- Powder for injection 3 g (2 g ampicillin sodium per 1 g sulbactam sodium)
- Powder for injection 10 g (10 g ampicillin sodium per 5 g sulbactam sodium)

Mechanism of Action

Pharmacology

Ampicillin inhibits bacterial cell wall mucopeptide synthesis. Sulbactam inhibits plasmid-medicated beta-lactamase enzymes commonly found in microorganisms resistant to ampicillin.

Indications and Usage

Treatment of infections of skin and skin structure, intra-abdominal and gynecologic infections caused by susceptible microorganisms, and mixed infections caused by ampicillin-susceptible organisms and beta-lactamase–producing organisms.

Contraindications

Hypersensitivity to penicillins, cephalosporins, or imipenem.

Dosage and Administration

Adults

IV/IM 1.5 to 3 g every 6 h, not to exceed 4 g/day sulbactam (1.5 g of product contains 0.5 g sulbactam).

Children 1 yr of age or older (less than 40 kg)

IV 300 mg/kg/day (200 mg ampicillin/100 mg sulbactam) in divided doses every 6 h.

Children at least 40 kg

IV Dose according to adult recommended doses; do not exceed total sulbactam dose of 4 g/day.

Storage/Stability

Keep refrigerated after reconstitution. Medication is stable for 2 h at room temperature, 72 h if refrigerated. Store at or below 86°F prior to reconstitution.

Drug Interactions

Allopurinol

Increases potential for ampicillin-induced skin rash.

Contraceptives, oral

May reduce efficacy of oral contraceptives.

Tetracyclines

May impair bactericidal effects of ampicillin/sulbactam.

Incompatibility

Do not mix with aminoglycosides (eg, gentamicin).

Laboratory Test Interactions

May cause false-positive urine glucose test results with Benedict solution, Fehling solution, or Clinitest tablets (enzyme-based tests; eg, Clinistix , Tes-tape , are recommended); false-positive direct Coombs test result in certain patient groups; false-positive protein reactions with sulfosalicylic acid and boiling test, acetic acid test, biuret reaction and nitric acid test (the bromphenol blue test, Multistix , is recommended).

Adverse Reactions

Cardiovascular

Thrombophlebitis at injection site.

CNS

Dizziness; fatigue; insomnia; reversible hyperactivity.

Dermatologic

Urticaria; maculopapular to exfoliative dermatitis; vesicular eruptions; erythema multiforme; skin rashes.

EENT

Itchy eyes; laryngospasm; laryngeal edema.

GI

Diarrhea; pseudomembranous colitis.

Genitourinary

Interstitial nephritis (eg, oliguria, proteinuria, hematuria, hyaline casts, pyuria); nephropathy; increased BUN and creatinine; vaginitis.

Hematologic

Decreased Hgb, Hct, RBC, WBC, neutrophils, lymphocytes, platelets; increased lymphocytes, monocytes, basophils, eosinophils, and platelets.

Metabolic

Elevated serum alkaline phosphatase, glutamic oxaloacetic transaminase, ALT, AST, and LDH; reduced serum albumin and total proteins.

Miscellaneous

Pain at injection site; hyperthermia.

Precautions

Pregnancy

Category B .

Lactation

Excreted in breast milk.

Children

Safety and efficacy not established.

Hypersensitivity

Reactions range from mild to life-threatening. Use cautiously in cephalosporin-sensitive patients because of possible cross-allergenicity.

Renal Function

Use cautiously with altered dosing interval.

Superinfection

May result in overgrowth of nonsusceptible bacterial or fungal organisms.

Overdosage

Symptoms

Hyperexcitability, convulsive seizures.

Patient Information

• Explain rationale for hospitalization during course of therapy.
• Inform patient of potential adverse reactions, and encourage a report of any problems.
• Encourage patient to increase fluid intake to 2,000 to 3,000 mL/day, unless contraindicated.
• Inform diabetic patients that this medication may cause false-positive glucose urine test results, and identify types that will be more reliable.
• If therapy is changed because of allergic reaction, explain significance of penicillin allergy, and inform of potential sensitivity to cephalosporins.