Clinical beta
FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.
Drug Monograph
Ampicillin–Sulbactam
Aminopenicillin + β-lactamase inhibitor
Indication
Aspiration pneumonia • Polymicrobial SSTI • Intra-abdominal (mild–moderate) • PID / endometritis • Mixed anaerobic/aerobic infections
INDICATIONS (CORE USE)
Aspiration pneumonia • Polymicrobial SSTI • Intra-abdominal (mild–moderate) • PID / endometritis • Mixed anaerobic/aerobic infections
ADULT DOSE (STANDARD)
IV 1.5–3 g q6h (combined product; severe infections: 3 g q6h)
MAX DOSE
Max: 12 g/day (combined product; adjust in renal impairment)
Route
IV, IM
PEDIATRIC DOSE
150–300 mg/kg/day (ampicillin component) IV divided q6h
Must-not-miss safety points
Major warning
- Penicillin hypersensitivity (anaphylaxis risk) - Hepatotoxicity (cholestatic pattern) - CDAD risk - No Pseudomonas coverage (avoid misuse) - Do NOT mix with aminoglycosides (IV inactivation)
USE IF: Aspiration pneumonia; mixed polymicrobial infections; mild–moderate intra-abdominal infection; gynecologic infections (e.g., PID, endometritis) when an IV β-lactam/β-lactamase inhibitor is appropriate. AVOID IF: Penicillin anaphylaxis; severe ESBL or AmpC-mediated resistance where regimen is inadequate; suspected Pseudomonas when antipseudomonal coverage is required. Ampicillin–sulbactam is an IV-only combination that restores ampicillin activity against many β-lactamase producers and adds anaerobic/polymicrobial utility—verify local resistance. Not suitable for oral step-down without alternative coverage.
ADULT DOSE
Standard IV: 1.5–3 g (combined product) every 6 hours; severe infections: 3 g q6h. Oral formulation not available. IM may be used when appropriate per local protocol.
PEDIATRIC DOSE
150–300 mg/kg/day (ampicillin component) IV divided q6h per neonatal/pediatric reference — verify ratio and sulbactam exposure limits.
MAX DOSE
Adult total combined product often capped near 12 g/day with sulbactam component not exceeding ~4 g/day — follow labeling and renal tables.
Practical Note
- Renal: reduce dose/extend interval per CrCl - Hepatic: monitor LFTs (cholestatic injury risk) - β-lactam: time-dependent killing → maintain dosing interval - Separate from aminoglycosides (IV line inactivation)
Clinical warnings
Adverse effects
Pediatrics
150–300 mg/kg/day (ampicillin component) IV divided q6h
Pregnancy
Generally used when indicated in pregnancy (historical FDA category B); align with current product labeling and obstetric guidance. Breastfeeding usually compatible with observation for infant GI symptoms. Generally considered safe (FDA pregnancy category B in legacy labeling); use when clinically indicated. Breastfeeding usually compatible — monitor infant for diarrhea or rash.
Lactation
See lactation references and product labeling.
Renal impairment
Dose-adjust by creatinine clearance; prolong interval and avoid accumulation — seizure risk increases with high levels.
Hepatic impairment
No routine dose adjustment; monitor LFTs and stop if hepatitis pattern worsens.
Elderly
Dose by CrCl; higher interaction and toxicity risk with polypharmacy.
IV preferred; IM if needed per protocol. IV push over 10–15 minutes or infusion 15–30 minutes per institutional guidance. Do NOT mix with aminoglycosides in same IV line — use separate lines and flush.
Clinical Picture
High doses or renal impairment → neurotoxicity (seizures), renal dysfunction
Immediate Actions
- Stop drug - Supportive care - Hydration - Monitor renal function and electrolytes
Antidote
No specific antidote — supportive care
Decontamination
Not applicable to typical IV use — contact poison center for massive accidental exposure.
Escalation
IV fluids; benzodiazepines for seizures; hemodialysis may enhance clearance in severe cases per nephrology/toxicology.
Common mistakes, resistance logic, and bedside traps
FIRST LINE: IV broad-spectrum β-lactam for polymicrobial and anaerobic infections. DOSE — Adult 1.5–3 g IV q6h (severe: 3 g q6h). MAX — 12 g/day combined (adjust in renal impairment; sulbactam ≤4 g/day). AVOID — CrCl <30 without adjustment; severe resistant pathogens (ESBL/AmpC, Pseudomonas). ANTIDOTE — None.
- Max 12 g/day (sulbactam ≤4 g/day) - No oral formulation → plan step-down early - Seizures risk ↑ in renal impairment - Hepatotoxicity (mixed/cholestatic) - CDAD risk - No Pseudomonas coverage - Separate from aminoglycosides (IV)
First-line IV option for aspiration pneumonia. No oral form — step down often to amoxicillin-clavulanate or other oral agent per susceptibility. Not for Pseudomonas or typical ESBL monotherapy scenarios. High-dose sulbactam for MDR Acinetobacter requires ID consultation. Always check CrCl before dosing. Separate from aminoglycosides.
- Bioavailability: IV only (100%) - Distribution: good tissue penetration - Protein binding: moderate - Elimination: predominantly renal - t½ prolonged in renal impairment - β-lactam: time-dependent killing
Ampicillin inhibits penicillin-binding proteins and disrupts bacterial cell wall synthesis. Sulbactam irreversibly inhibits many β-lactamases, protecting ampicillin; sulbactam also contributes intrinsic activity against some Acinetobacter strains in high-dose specialist regimens.
Saudi Arabia
Unasyn, Ampicillin–Sulbactam (generic)
Global
Ampicillin/Sulbactam injection
Common trade names are curated examples only — formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.
Saudi Arabia
International