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). |
| Molecular Weight | 388.48 |
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 | Penicillin V potassium crosses the placenta. Human studies have not demonstrated a risk of fetal malformations. It is considered safe for use during the first trimester if clinically indicated. |
| 2nd trimester | Penicillin V potassium is safe for use during the second trimester. No adverse fetal effects have been reported. |
| 3rd trimester | Penicillin V potassium is safe for use during the third trimester. No fetal or neonatal adverse effects have been reported. |
Clinical note
Comprehensive clinical and safety monograph for V-CILLIN K (V-CILLIN K).
| Placental transfer | Penicillin V potassium crosses the placenta. Fetal serum concentrations reach about 50% of maternal levels, but no adverse outcomes have been reported. |
| Breastfeeding | Penicillin V potassium is excreted into breast milk in low concentrations. It is generally considered compatible with breastfeeding, but potential for diarrhea and allergic sensitization in the infant exists. Monitor infant for rash or gastrointestinal disturbances. |
■ FDA Black Box Warning
No FDA boxed warning.
| Serious Effects |
Hypersensitivity to penicillin V potassium or any other penicillinHistory of severe immediate hypersensitivity reaction (e.g., anaphylaxis) to beta-lactam antibiotics
| 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. |
| Food/Dietary | May be taken with or without food; however, taking with food may reduce peak concentration but does not affect total absorption. Avoid acidic drinks like fruit juices that may degrade the drug. |
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| Lactation Rating | L1 (Safe) |
| 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. |
| 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. |
| Clinical Pearls | V-CILLIN K (penicillin V potassium) is acid-stable and can be taken with or without food, but food may decrease absorption. It is the preferred oral penicillin for streptococcal pharyngitis and prophylaxis of rheumatic fever. Ensure complete course to prevent resistance and recurrence. Monitor for hypersensitivity reactions; allergy to penicillins contraindicates use. |
| Patient Advice | Take exactly as prescribed, even if you feel better. · Complete the full course to prevent resistance. · Shake the oral suspension well before each dose. · Store at room temperature; do not freeze. · Notify doctor if rash, difficulty breathing, or swelling occurs. · Inform your doctor if you have kidney disease or allergies. |