PRINCIPEN '250'
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PRINCIPEN '250' (PRINCIPEN '250').
Ampicillin is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis and death.
| Metabolism | Ampicillin is primarily excreted unchanged by the kidneys via glomerular filtration and tubular secretion. Some hepatic metabolism occurs, but it is minimal. |
| Excretion | Primarily renal (60-80% unchanged), with some biliary/fecal excretion (approximately 10-20%) |
| Half-life | 1.0-1.5 hours in normal renal function; prolongation in renal impairment requires dose adjustment |
| Protein binding | 20-25% bound to serum albumin |
| Volume of Distribution | 0.2-0.3 L/kg, indicating limited extravascular distribution |
| Bioavailability | Oral: 25-40% (acid-labile, food reduces absorption) |
| Onset of Action | Oral: 30-60 minutes; IM: 15-30 minutes |
| Duration of Action | 4-6 hours; shorter in severe renal impairment |
250 mg orally every 6 hours
| Dosage form | CAPSULE |
| Renal impairment | CrCl 10-50 mL/min: 250 mg every 12-24 hours; CrCl <10 mL/min: 250 mg every 24-48 hours |
| Liver impairment | No dosage adjustment required for mild to moderate hepatic impairment. Severe impairment (Child-Pugh C): reduce dose by 50% or extend interval to every 12 hours |
| Pediatric use | Children >1 month: 12.5-25 mg/kg orally every 6 hours; maximum 4 g/day |
| Geriatric use | Monitor renal function; adjust dose based on CrCl as for adults with renal impairment. Avoid in elderly with CrCl <10 mL/min unless necessary. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PRINCIPEN '250' (PRINCIPEN '250').
| Breastfeeding | Ampicillin is excreted in breast milk in low concentrations. M/P ratio approximately 0.1-0.2. Considered compatible with breastfeeding by American Academy of Pediatrics; monitor infant for diarrhea and candidiasis. |
| Teratogenic Risk | FDA Pregnancy Category B. Animal studies show no fetal risk, but no adequate human studies in first trimester. No known teratogenicity; use during pregnancy only if clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["History of allergic reaction to any penicillin","Infections caused by penicillinase-producing organisms"]
| Precautions | ["Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) have been reported; contraindicated in patients with penicillin allergy.","Clostridium difficile-associated diarrhea (CDAD) can occur and may range in severity from mild diarrhea to fatal colitis.","Prolonged use may result in overgrowth of nonsusceptible organisms, including fungi; superinfection may occur.","Use with caution in patients with renal impairment; dosage adjustment may be necessary.","Cases of drug-induced hepatitis and cholestatic jaundice have been reported."] |
Loading safety data…
| Monitor maternal renal function, liver function, and CBC periodically during prolonged therapy. In neonates, monitor for signs of hypersensitivity or diarrhea if maternal use near term. |
| Fertility Effects | No known adverse effects on fertility based on animal studies and clinical data. No evidence of impaired male or female fertility. |