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. |
| Molecular Weight | 496.6 |
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 | Generally considered safe; no known teratogenic effects in humans. |
| 2nd trimester | Safe for use; no fetal risk demonstrated. |
| 3rd trimester | Safe; potential for maternal/fetal effects only with high doses (e.g., seizures). |
Clinical note
Comprehensive clinical and safety monograph for POLYCILLIN-N (POLYCILLIN-N).
| Placental transfer | Crosses placenta; achieves fetal serum levels 10–50% of maternal levels. |
| Breastfeeding | Excreted into breast milk in low concentrations; unlikely to cause adverse effects in infants. Use with caution in premature infants or those with renal impairment. |
| Lactation Rating |
■ 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 |
History of anaphylactic reaction to penicillinsHypersensitivity to procaine or other ester-type local anestheticsProcaine sensitivity
| 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) |
| Food/Dietary |
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| L1 (Safe) |
| 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 | : 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. |
| No significant food interactions. However, oral ampicillin absorption may be decreased when taken with food; take on an empty stomach (1 hour before or 2 hours after meals) for optimal absorption. For intravenous administration, no dietary restrictions. |
| Clinical Pearls | POLYCILLIN-N (ampicillin sodium/sulbactam sodium) is a beta-lactam/beta-lactamase inhibitor combination. It is not active against MRSA or Pseudomonas aeruginosa. Dose adjustment required in renal impairment (CrCl <30 mL/min). May cause false-positive urine glucose tests with Clinitest but not with Clinistix. Monitor for rash, especially in patients with mononucleosis or CMV infection due to high incidence of ampicillin-induced rash. |
| Patient Advice | Take this medication exactly as prescribed, even if you feel better. Complete the full course. · If you are taking this by mouth, take with a full glass of water. For injection, do not miss doses. · Common side effects include diarrhea, nausea, and rash. Contact your doctor if you have severe diarrhea or a spreading rash. · Inform your doctor if you have kidney disease, are allergic to penicillin or cephalosporins, or are taking oral contraceptives (efficacy may be reduced). · Avoid alcohol while on this medication to reduce risk of stomach upset. |