Classifications: antibiotic; aminopenicillin;

Prototype: Ampicillin
Pregnancy Category: B


1.5 g, 3 g vials


Ampicillin inhibits the final stage of bacterial cell wall synthesis by binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall. This results in bacteria cell wall lysis and death. Sulbactam inhibits beta-lactamases, most frequently responsible for transferred drug resistance. Thus the spectrum of drugs affected by the combination of the two is increased.

Therapeutic Effect

Effective against both gram-positive and gram-negative bacteria including those that produce beta-lactamase and nonbeta-lactamase producers. Ampicillin without sulbactam is not effective against beta-lactamase producing strains.


Treatment of infections due to susceptible organisms in skin and skin structures, intraabdominal infections, and gynecologic infections.


Hypersensitivity to penicillins; mononucleosis.

Cautious Use

Hypersensitivity to cephalosporins; GI disorders; renal disease or impairment; pregnancy (category B) or lactation.

Route & Dosage

Systemic Infections
Adult/Child (> 40 kg): IV/IM 1.5–3 g q6h (max: 4 g sulbactam/d)
Child (≥1 y): IV 300 mg/kg/d (200 mg/kg ampicillin and 100 mg/kg sulbactam) divided q6h

Renal Impairment
Clcr >30 mL/min: give q6–8h; 15–29 mL/min: give q12h; 5–14 mL/min: give q24h
Dialysis: Give dose after dialysis


  • Reconstitute solution with sterile water for injection by adding 6.4 mL diluent to a 3 g vial. Each mL contains 250 mg ampicillin and 125 mg sulbactam.
  • Give deep IM into a large muscle. Rotate injection sites.

PREPARE: Direct/Intermittent: Reconstitute each 1.5 g vial with 3.2 mL of sterile water for injection to yield 375 mg/mL (250 mg ampicillin/125 mg sulbactam); must further dilute with NS, D5W, D5/NS, D5W/0.45NS, or RL to a final concentration within the range of 3–45 mg/mL.  

ADMINISTER: Direct: Give slowly over at least 10–15 min.  Intermittent: ??Infuse solutions of less than 50 mL over 10–15 min and solutions of 50–100 mL over 15–30 min. With solutions of 100 mL or more, set rate according to amount of solution but no faster than direct IV rate (e.g., 100 mL over 30 min). ??Convulsions may be induced by too rapid administration. ??Use only freshly prepared solution; administer within 1 h after preparation. 

INCOMPATIBILITIES Solution/additive: Do not add to a dextrose-containing solution unless entire dose is given within 1 h of preparation. Ciprofloxacin. Y-site: Amiodarone, amphotericin B, ciprofloxacin, idarubicin, lansoprazole, nicardipine, ondansetron, sargramostim.

  • Store powder for injection at 15°–30° C (59°–86° F) before reconstitution. Storage times and temperatures vary for different concentrations of reconstituted solutions; consult manufacturer's directions.

Adverse Effects (≥1%)

Body as a Whole: Hypersensitivity (rash, itching, anaphylactoid reaction), fatigue, malaise, headache, chills, edema. GI: Diarrhea, nausea, vomiting, abdominal distention, candidiasis. Hematologic: Neutropenia, thrombocytopenia. Urogenital: Dysuria. CNS: Seizures. Other: Local pain at injection site; thrombophlebitis.


Drug: Allopurinol increases incidence of rash; effectiveness of the aminoglycosides may be impaired in patients with severe end stage renal disease; chloramphenicol, erythromycin, tetracycline may reduce bactericidal effects of ampicillin—this interaction is primarily significant when low doses are used; ampicillin may interfere with the contraceptive action of oral contraceptives—female patients should be advised to consider nonhormonal contraception while on antibiotics.


Peak: Immediate after IV. Duration: 6–8 h. Distribution: Most body tissues; high CNS concentrations only with inflamed meninges; crosses placenta; appears in breast milk. Metabolism: Minimal hepatic metabolism. Elimination: In urine. Half-Life: 1 h.

Nursing Implications

Assessment & Drug Effects

  • Determine previous hypersensitivity reactions to penicillins, cephalosporins, and other allergens prior to therapy.
  • Lab tests: Baseline C&S tests prior to initiation of therapy; start drug pending results.
  • Report promptly unexplained bleeding (e.g., epistaxis, purpura, ecchymoses).
  • Monitor patient carefully during the first 30 min after initiation of IV therapy for signs of hypersensitivity and anaphylactoid reaction (see Appendix F). Serious anaphylactoid reactions require immediate use of emergency drugs and airway management.
  • Observe for and report symptoms of superinfections (see Appendix F). Withhold drug and notify physician.
  • Monitor I&O ratio and pattern. Report dysuria, urine retention, and hematuria.

Patient & Family Education

  • Report chills, wheezing, pruritus (itching), respiratory distress, or palpitations to physician immediately.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

© 2006-2023 Last Updated On: 02/02/2023 (0)
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