Ampicillin-Sulbactam
Unasyn
Aminopenicillin + β-lactamase inhibitor
Ampicillin (cell-wall inhibitor) + sulbactam (β-lactamase inhibitor) → restores activity vs β-lactamase producers; gram-positive, some gram-negative, anaerobes.
Indications
- •Head/neck + intra-abdominal surgical prophylaxis/infection
- •Polymicrobial soft-tissue infection
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Surgical prophylaxis | 3 g IV within 60 min; redose q2h (short half-life) | — |
Pharmacokinetics
Half-life ~1 h → redose q2h intraop. Renally cleared.
Side effects
- !Penicillin allergy/anaphylaxis
- !Rash (esp. with EBV/mono)
- !C. difficile
Contraindications
- ×Penicillin allergy
Clinical pearls
- ★Short half-life → q2h intraoperative redosing (a common prophylaxis-timing miss).
- ★Good head-and-neck prophylaxis choice (oral flora + anaerobes).
Other drugs in Antibiotics
- Cefazolin
β-lactam — inhibits bacterial cell wall PBPs.
- Vancomycin
Inhibits cell wall synthesis (binds D-Ala-D-Ala). Active against MRSA + gram-positives.
- Clindamycin
Binds 50S ribosomal subunit, blocks peptide-bond formation. Bacteriostatic against most organisms; bactericidal against susceptible streptococci. Excellent activity against anaerobes and gram-positive cocci including community-acquired MRSA.
- Gentamicin
Binds 30S ribosomal subunit, causes misreading of mRNA → defective bacterial protein synthesis. Bactericidal, concentration-dependent killing. Synergy with cell-wall agents (β-lactams, vancomycin) for gram-positive endocarditis.
- Cefuroxime
β-lactam — inhibits cell-wall synthesis (PBP binding). 2nd-gen: gram-positive + expanded gram-negative.
- Cefepime
β-lactam cell-wall inhibitor. Broad gram-negative (incl. Pseudomonas) + gram-positive coverage.
- Cefotetan
β-lactam; adds anaerobic (B. fragilis) coverage → colorectal/gynecologic prophylaxis.
- Cefotaxime
β-lactam cell-wall inhibitor. Broad gram-negative + CNS penetration.
Browse all classes: /reference/drugs
Suggested reading
- •Miller's Anesthesia, 9e
- •FDA package insert
