PENAPAR-VK
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PENAPAR-VK (PENAPAR-VK).
Penicillin V is a bactericidal antibiotic that inhibits cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidation, and activating autolytic enzymes.
| Metabolism | Penicillin V is primarily metabolized by hydrolysis to penicilloic acid, which is inactive. Minor hepatic metabolism occurs. Approximately 60-80% is excreted unchanged in urine. |
| Excretion | Primarily renal excretion (tubular secretion) of unchanged drug (~90%); minor biliary/fecal elimination (<10%). |
| Half-life | Terminal elimination half-life: 0.5–1 hour in normal renal function; prolonged to 7–10 hours in severe renal impairment (anuria). Requires dose adjustment in renal failure. |
| Protein binding | ~80% bound primarily to albumin. |
| Volume of Distribution | 0.2–0.3 L/kg; limited distribution due to high protein binding and rapid renal clearance; does not cross blood-brain barrier significantly in absence of inflammation. |
| Bioavailability | Oral: 60–73% (variable due to food effect; take on empty stomach). |
| Onset of Action | Oral: 30–60 minutes (peak serum concentration at 1 hour); IM: 15–30 minutes; IV: immediate. |
| Duration of Action | 6–8 hours for susceptible organisms; may persist longer if renal impairment present. Rebound bacteriostatic effect noted up to 2–4 hours after serum levels fall below MIC. |
250-500 mg orally every 6 hours; maximum 2 g/day.
| Dosage form | FOR SOLUTION |
| Renal impairment | CrCl <10 mL/min: 250 mg every 12 hours; CrCl 10-50 mL/min: 250-500 mg every 6-8 hours. |
| Liver impairment | No adjustment required for mild to moderate impairment; use caution in severe impairment. |
| Pediatric use | Neonates: 20-30 mg/kg/day divided every 12 hours; Infants and children: 25-50 mg/kg/day divided every 6 hours; maximum 3 g/day. |
| Geriatric use | No specific adjustment required; monitor renal function and adjust accordingly based on CrCl. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PENAPAR-VK (PENAPAR-VK).
| Breastfeeding | Penicillin VK is excreted into breast milk in small amounts (M/P ratio approximately 0.1-0.2). Considered compatible with breastfeeding by the American Academy of Pediatrics. Risk of infant sensitization or diarrhea; monitor infant for rash, diarrhea, or candidiasis. |
| Teratogenic Risk | FDA Pregnancy Category B. Penicillin VK crosses the placenta. No evidence of teratogenicity in animal studies. First trimester: theoretical risk due to alterations in gut flora, but no known teratogenic effects. Second and third trimesters: safe for treatment of infections; avoid high doses near term due to risk of neonatal hemolytic anemia or sensitization. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to penicillins or any component of the formulation","Hypersensitivity to cephalosporins or other beta-lactam antibiotics (cross-sensitivity)"]
| Precautions | ["Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) can occur.","Clostridium difficile-associated diarrhea (CDAD) may develop.","Use with caution in patients with renal impairment due to risk of neurotoxicity.","Prolonged use may result in superinfection.","Use with caution in patients with a history of allergy, asthma, or hay fever."] |
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| Fetal Monitoring | Monitor maternal renal function and CBC. In pregnancy, assess for signs of infection resolution. No specific fetal monitoring required except when used for group B Streptococcus prophylaxis during labor (standard intrapartum monitoring). |
| Fertility Effects | No known adverse effects on fertility in animal or human studies. Penicillin VK does not affect spermatogenesis, ovulation, or implantation. |