PRINCIPEN '125'
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PRINCIPEN '125' (PRINCIPEN '125').
Ampicillin is a penicillin beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins, leading to cell lysis.
| Metabolism | Ampicillin is metabolized by hydrolysis to penicilloic acid, primarily in the liver. It also undergoes renal tubular secretion. |
| Excretion | Renal: approximately 60-80% of the dose excreted unchanged in urine via tubular secretion and glomerular filtration. Biliary/fecal: minimal, <10%. |
| Half-life | Terminal elimination half-life: 0.7-1.4 hours in adults with normal renal function. Prolonged in renal impairment (up to 7-10 hours in anuria). |
| Protein binding | Approximately 20-30% bound to serum proteins, primarily albumin. |
| Volume of Distribution | 0.3-0.4 L/kg, approximating extracellular fluid volume. Higher in neonates and critically ill patients due to increased extracellular water. |
| Bioavailability | Oral: 30-50% due to acid lability and incomplete absorption. IM: nearly 100%. |
| Onset of Action | Oral: 30-60 minutes after oral administration. IM: 15-30 minutes. Intravenous: immediate. |
| Duration of Action | 4-6 hours for susceptible organisms when administered every 6 hours. Clinical effect persists as long as serum levels exceed MIC. |
250-500 mg orally every 6 hours for mild to moderate infections; 500 mg to 1 g every 6 hours for severe infections.
| Dosage form | FOR SUSPENSION |
| Renal impairment | CrCl 10-50 mL/min: Administer every 6-12 hours. CrCl <10 mL/min: Administer every 12-16 hours. |
| Liver impairment | No dose adjustment required. |
| Pediatric use | Infants and children: 12.5-25 mg/kg orally every 6 hours. For severe infections: up to 50 mg/kg/day in divided doses every 6 hours. |
| Geriatric use | Dose based on renal function; use lower end of dosing interval due to age-related decline in renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PRINCIPEN '125' (PRINCIPEN '125').
| Breastfeeding | Excreted into breast milk in low amounts (M/P ratio approximately 0.5). Considered compatible with breastfeeding; monitor infant for rash, diarrhea, or candidiasis. |
| Teratogenic Risk | FDA Pregnancy Category B. No evidence of teratogenicity in animal studies. Inadequate human data in first trimester; risk cannot be excluded. Penicillins are generally considered low risk throughout pregnancy. |
| Fetal Monitoring |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to penicillins, cephalosporins, or other beta-lactam antibiotics.","Infections caused by beta-lactamase-producing organisms (ampicillin is susceptible to beta-lactamase degradation)."]
| Precautions | ["Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) have occurred.","Clostridium difficile-associated diarrhea (CDAD) reported with nearly all antibacterial agents.","Prolonged use may result in overgrowth of nonsusceptible organisms including fungi.","Dosage adjustment required in renal impairment.","Safety in pregnancy: Category B; use only if clearly needed."] |
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| Monitor maternal renal function if high doses used. No specific fetal monitoring required unless allergic reaction occurs. |
| Fertility Effects | No known adverse effects on fertility. Animal studies show no impairment. |