VERSAPEN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VERSAPEN (VERSAPEN).
Bactericidal; inhibits cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting peptidoglycan cross-linking.
| Metabolism | Partially metabolized to penicilloic acid; primarily renal excretion via tubular secretion and glomerular filtration. |
| Excretion | Renal: 60-70% unchanged via glomerular filtration and tubular secretion. Biliary: <10% excreted unchanged. Fecal: 20-30% as metabolites. |
| Half-life | 0.5-1.0 hour (normal renal function); prolonged to 10-20 hours in anuria. Requires dose adjustment in renal impairment. |
| Protein binding | 18-22% bound to albumin. |
| Volume of Distribution | 0.3-0.5 L/kg. Moderate Vd indicates distribution into extracellular fluid; limited CNS penetration unless inflamed meninges. |
| Bioavailability | IM: ~90%; Oral: 30-50% (highly variable due to gastric acid instability and first-pass metabolism). |
| Onset of Action | IV: immediate; IM: 15-30 minutes; Oral: 30-60 minutes. Onset faster with IV due to rapid bactericidal levels. |
| Duration of Action | IM/IV: 4-6 hours; Oral: 6-8 hours. Duration limited by rapid renal clearance and susceptibility to beta-lactamase. |
| Molecular Weight | 309.34 |
500 mg IV every 6 hours or 1 g IV every 8 hours for moderate infections; 2 g IV every 4 hours for severe infections.
| Dosage form | FOR SUSPENSION |
| Renal impairment | CrCl >50 mL/min: 500 mg-1 g every 6 hours; CrCl 10-50 mL/min: 500 mg every 6-12 hours; CrCl <10 mL/min: 500 mg every 12-24 hours. |
| Liver impairment | No specific guidelines; caution in severe hepatic impairment (Child-Pugh C) due to potential accumulation; consider dose reduction based on clinical response and tolerance. |
| Pediatric use | Infants >1 month: 25-50 mg/kg IV every 6 hours; maximum 2 g per dose. Neonates: 25 mg/kg IV every 12 hours (0-7 days) or every 8 hours (8-28 days). |
| Geriatric use | No specific dose adjustment is required other than based on renal function; monitor for renal impairment and adjust according to CrCl. |
| 1st trimester | Associated with congenital anomalies in animal studies; avoid unless essential. |
| 2nd trimester | Use only if clearly needed; risk of altered gut flora and diarrhea in neonates. |
| 3rd trimester | Use only if clearly needed; risk of kernicterus in premature infants. |
Clinical note
Comprehensive clinical and safety monograph for VERSAPEN (VERSAPEN).
| Placental transfer | Crosses the placenta with fetal serum concentrations reaching 10-50% of maternal levels. |
| Breastfeeding | Excreted into breast milk in low amounts; not expected to cause adverse effects in infants. Caution in neonates with hyperbilirubinemia or glucose-6-phosphate dehydrogenase deficiency. |
| Lactation Rating |
■ FDA Black Box Warning
Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) have been reported in patients on penicillin therapy.
| Serious Effects |
Hypersensitivity to penicillinsInfectious mononucleosis
| Precautions | Severe hypersensitivity reactions including anaphylaxis; pseudomembranous colitis; superinfection; caution in renal impairment; risk of neurotoxicity with high doses. |
| Food/Dietary | No significant food interactions; absorption is not affected by food. Avoid alcohol as it may increase risk of side effects. |
| Clinical Pearls |
Loading safety data…
| L2 (Probably Compatible) |
| Teratogenic Risk | VERSAPEN (hetacillin) is a penicillin-class antibiotic. Animal studies have not revealed evidence of fetal harm. There are no adequate and well-controlled studies in pregnant women. However, penicillins are generally considered low risk in pregnancy. Use only if clearly needed. Risk cannot be ruled out. First trimester: No known teratogenicity. Second trimester: No known adverse fetal effects. Third trimester: No known adverse fetal effects; theoretical risk of alteration of gut flora. |
| Fetal Monitoring | Monitor for signs of hypersensitivity reactions (rash, urticaria, anaphylaxis) in mother. No specific fetal monitoring required. Observe for maternal gastrointestinal effects (nausea, diarrhea). Prolonged use may lead to bacterial or fungal superinfection. No routine laboratory monitoring necessary. |
| Fertility Effects | No known adverse effects on fertility. Animal studies have not shown impaired fertility. No human data available. |
| VERSAPEN (hetacillin) is a prodrug of ampicillin; monitor for hypersensitivity reactions, especially in penicillin-allergic patients. Adjust dose in renal impairment (CrCl <30 mL/min). May cause false-positive urine glucose tests with Clinitest but not with glucose oxidase methods. Not effective against penicillinase-producing organisms. |
| Patient Advice | Take exactly as prescribed; complete the full course even if you feel better. · Do not take if you are allergic to penicillins or cephalosporins. · Report any rash, itching, or difficulty breathing immediately. · Take with a full glass of water; may be taken with or without food. · Store at room temperature away from moisture and heat. · Do not use after the expiration date. |