POLYCILLIN-N
Clinical safety rating: caution
Comprehensive clinical and safety monograph for POLYCILLIN-N (POLYCILLIN-N).
Ampicillin is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking, and activating autolytic enzymes. It is bactericidal against susceptible organisms.
| Metabolism | Ampicillin is metabolized via hydrolysis to penicilloic acid, primarily in the liver; the major metabolite is the inactive penicilloic acid. It also undergoes renal tubular secretion and glomerular filtration. |
| Excretion | Renal: 60-80% unchanged via glomerular filtration and tubular secretion. Biliary: ~20% excreted in bile and feces. Small amount metabolized to penicilloic acid. |
| Half-life | Terminal elimination half-life: 0.5-1 hour (normal renal function); increases to 7-10 hours in anuria. Prolonged in neonates (2-4 hours). |
| Protein binding | Ampicillin: 15-25% bound to serum albumin (primarily albumin). Binding is saturable at high concentrations. |
| Volume of Distribution | Vd: 0.3-0.4 L/kg (adults). Reflects distribution into total body water; penetrates into CSF only with inflamed meninges. |
| Bioavailability | Oral: 40-60% (not applicable for Polycillin-N, which is parenteral). IM: 100% (complete). IV: 100%. |
| Onset of Action | IV: Immediate (within minutes). IM: 15-30 minutes. Oral: 30-60 minutes (though oral form is not Polycillin-N, which is parenteral). |
| Duration of Action | 6-8 hours (depending on dose and renal function). Clinical effect correlates with serum concentrations > MIC for susceptible organisms. |
1-2 g IV/IM every 4-6 hours
| Dosage form | INJECTABLE |
| Renal impairment | CrCl 30-50 mL/min: 1-2 g every 6 hours; CrCl 10-29 mL/min: 1-2 g every 8 hours; CrCl <10 mL/min: 1-2 g every 12 hours |
| Liver impairment | No specific adjustment required; use with caution in severe hepatic impairment |
| Pediatric use | Neonates <7 days: 100 mg/kg/day divided every 12 hours; Neonates 7-28 days: 150 mg/kg/day divided every 8 hours; Infants and children: 200-400 mg/kg/day IV/IM divided every 4-6 hours |
| Geriatric use | No specific dose adjustment; monitor renal function and adjust based on creatinine clearance |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for POLYCILLIN-N (POLYCILLIN-N).
| Breastfeeding | Penicillins are excreted in breast milk in low concentrations; minimal risk to nursing infant. M/P ratio not established for this specific formulation. Compatible with breastfeeding; monitor infant for potential GI disturbances or allergic reactions. |
| Teratogenic Risk | FDA Pregnancy Category B. No evidence of teratogenicity in animal studies. Adequate and well-controlled studies in pregnant women are lacking. Fetal risk cannot be ruled out; use only if clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
Serious and occasionally fatal hypersensitivity reactions (including anaphylaxis) have been reported in patients on penicillin therapy. Clostridium difficile-associated diarrhea (CDAD) has been reported with nearly all antibacterial agents, including ampicillin.
| Serious Effects |
["Hypersensitivity to ampicillin, any penicillin, or any component of the formulation","Infections caused by beta-lactamase-producing organisms (unless combined with a beta-lactamase inhibitor)","Infectious mononucleosis (high incidence of maculopapular rash)"]
| Precautions | ["Hypersensitivity reactions: Serious and occasionally fatal anaphylaxis may occur; discontinue therapy if allergic reaction suspected","Clostridium difficile-associated diarrhea (CDAD): Consider in patients presenting with diarrhea; may range from mild to life-threatening","Superinfection: Prolonged use may result in overgrowth of nonsusceptible organisms including fungi","Hematologic effects: Prolonged therapy may cause neutropenia, thrombocytopenia, or anemia","Renal impairment: Dose adjustment required in severe renal insufficiency","Drug interactions: Probenecid decreases renal excretion; allopurinol increases risk of rash","Pediatric use: Safety and efficacy established except for neonates with hyperbilirubinemia (risk of kernicterus)"] |
Loading safety data…
| : Monitor maternal renal function and signs of hypersensitivity (rash, anaphylaxis). No specific fetal monitoring required; assess for therapeutic response and adverse effects. |
| Fertility Effects | No known adverse effects on fertility in animal studies. Human data limited; no expected impact on reproduction. |