V-CILLIN K
Clinical safety rating: caution
Comprehensive clinical and safety monograph for V-CILLIN K (V-CILLIN K).
Penicillin V exerts bactericidal activity by inhibiting bacterial cell wall synthesis through binding to penicillin-binding proteins (PBPs), inhibiting transpeptidase activity, and disrupting peptidoglycan cross-linking.
| Metabolism | Primarily metabolized in the liver via hydrolysis to inactive metabolites. Minor renal elimination of unchanged drug. |
| Excretion | Renal: 60-90% unchanged via tubular secretion and glomerular filtration; minor biliary/fecal: <10%. |
| Half-life | 0.5–1 hour (normal renal function); prolonged to 2–6 hours in renal impairment. |
| Protein binding | 60–80% bound to serum albumin. |
| Volume of Distribution | 0.2–0.4 L/kg; distributes into extracellular fluid, limited CNS penetration unless meninges inflamed. |
| Bioavailability | Oral: 60–70% (acid-labile, food decreases absorption). |
| Onset of Action | Oral: 30–60 minutes (peak serum concentration at 0.5–1 hour). |
| Duration of Action | 4–6 hours (bactericidal levels maintained for 4–6 hours after oral dose). |
250-500 mg orally every 6 hours for mild to moderate infections; 500 mg orally every 6 hours for severe infections.
| Dosage form | FOR SOLUTION |
| Renal impairment | CrCl >50 mL/min: no adjustment; CrCl 10-50 mL/min: no adjustment needed but consider extended intervals for high doses; CrCl <10 mL/min: 250-500 mg every 12-16 hours. |
| Liver impairment | No adjustment required for mild to moderate hepatic impairment; use with caution in severe impairment due to risk of accumulation. |
| Pediatric use | Children <12 years: 25-50 mg/kg/day orally divided every 6-8 hours; maximum 3 g/day. |
| Geriatric use | No specific dose adjustment; monitor renal function and adjust based on CrCl. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for V-CILLIN K (V-CILLIN K).
| Breastfeeding | Penicillin V is excreted into breast milk in low concentrations. The milk-to-plasma ratio is approximately 0.2. It is generally considered compatible with breastfeeding, but may cause diarrhea, candidiasis, or allergic sensitization in the infant. The American Academy of Pediatrics classifies penicillin V as usually compatible with breastfeeding. |
| Teratogenic Risk | Penicillin V (V-CILLIN K) is classified as FDA Pregnancy Category B. Animal reproduction studies have not demonstrated a risk to the fetus, and there are no adequate and well-controlled studies in pregnant women. However, penicillin V is generally considered safe for use during pregnancy. There is no evidence of teratogenicity in the first trimester; risk is low across all trimesters. If used for treatment of syphilis, there is a risk of Jarisch-Herxheimer reaction, which may induce preterm labor or fetal distress. |
■ FDA Black Box Warning
No FDA boxed warning.
| Serious Effects |
Hypersensitivity to penicillins or any component of the formulation. Use with caution in patients with history of immediate hypersensitivity reactions to cephalosporins.
| Precautions | Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) may occur. Use with caution in patients with history of allergies, asthma, or renal impairment. Monitor for superinfection with prolonged use. Avoid use in patients with mononucleosis due to high incidence of morbilliform rash. |
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| Fetal Monitoring | No specific maternal-fetal monitoring is required beyond standard obstetric care. Monitor for maternal allergic reactions (rash, anaphylaxis) and for signs of Jarisch-Herxheimer reaction when treating syphilis in pregnancy. In preterm labor or with prolonged use, monitor infant for gastrointestinal disturbances or candidiasis. |
| Fertility Effects | No known adverse effects on fertility. Penicillin V does not impair reproductive function in animal studies, and no human data suggest negative impact on fertility. |