V-CILLIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for V-CILLIN (V-CILLIN).
Penicillin G (V-CILLIN) inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidase activity and autolysin activation, leading to cell lysis.
| Metabolism | Penicillin G is primarily excreted unchanged in urine; metabolism is minor with hydrolysis to penicilloic acid. |
| Excretion | Primarily renal (60-70% unchanged via tubular secretion); minor biliary/fecal elimination (<10%). |
| Half-life | Terminal elimination half-life ~30-60 minutes in normal renal function; prolonged in renal impairment (up to 10 hours in anuria). |
| Protein binding | Approximately 60-80%, primarily to serum albumin. |
| Volume of Distribution | 0.3-0.5 L/kg, indicating distribution mainly into extracellular fluid. |
| Bioavailability | Oral: 25-35% (acid-labile, food reduces absorption); IM: nearly 100%. |
| Onset of Action | Oral: 30-60 minutes; IM: 15-30 minutes. |
| Duration of Action | Short (~4-6 hours for oral) requiring frequent dosing; prolonged with probenecid coadministration. |
| Molecular Weight | 350.45 |
250-500 mg orally every 8 hours or 500 mg every 12 hours for mild to moderate infections.
| Dosage form | FOR SUSPENSION |
| Renal impairment | CrCl 10-50 mL/min: 250-500 mg every 12 hours. CrCl <10 mL/min: 250-500 mg every 24 hours. |
| Liver impairment | No specific dose adjustment recommended for Child-Pugh A, B, or C; caution in severe impairment due to decreased clearance. |
| Pediatric use | Children >12 years: 25-50 mg/kg/day divided every 8 hours for mild/moderate infections; up to 100 mg/kg/day for severe infections. Maximum 3 g/day. |
| Geriatric use | Adjust based on renal function; increased risk of toxicity due to age-related GFR decline. |
| 1st trimester | Penicillin V is generally considered safe in the first trimester. Animal studies have not shown fetal harm, and there are no adequate controlled studies in pregnant women, but the risk appears low. |
| 2nd trimester | Safe for use in the second trimester. No specific risks have been associated with penicillin V. |
| 3rd trimester | Safe for use in the third trimester. Penicillin V is often used to prevent group B streptococcal infection in neonates. |
Clinical note
Comprehensive clinical and safety monograph for V-CILLIN (V-CILLIN).
| Placental transfer | Penicillin V crosses the placenta to a limited extent, with fetal serum concentrations about 10-15% of maternal levels. |
| Breastfeeding | Penicillin V is excreted into breast milk in low concentrations, unlikely to cause adverse effects in nursing infants. Compatible with breastfeeding, but monitor for potential gastrointestinal disturbances (e.g., diarrhea, candidiasis). |
■ FDA Black Box Warning
No FDA black box warning for V-CILLIN.
| Serious Effects |
Hypersensitivity to penicillinsHypersensitivity to any component of the formulation
| Precautions | Hypersensitivity reactions (anaphylaxis, urticaria), Severe cutaneous adverse reactions (SCARs including SJS, TEN), Clostridioides difficile-associated diarrhea (CDAD), Renal impairment (dose adjustment may be needed), Use in neonates and infants (monitor for toxicity) |
| Food/Dietary | Food does not significantly affect absorption, but taking with food may reduce gastrointestinal upset. Avoid acidic fruit juices (e.g., orange, grapefruit) within 1 hour of dosing as they can degrade the antibiotic. No other specific food interactions. |
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| Lactation Rating | L1 (Safe) |
| Teratogenic Risk | Penicillin V (V-CILLIN) is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, and there are no adequate well-controlled studies in pregnant women. However, penicillin V is generally considered safe in all trimesters. There is no evidence of teratogenicity in humans. Use only if clearly needed. |
| Fetal Monitoring | No specific maternal-fetal monitoring is required beyond standard prenatal care. Monitor for signs of allergic reaction or superinfection. For prolonged therapy, monitor renal and hematologic function. |
| Fertility Effects | No known adverse effects on fertility. Penicillin V does not impact reproductive function in animal studies. No human data suggest impairment of fertility. |
| Clinical Pearls |
| V-CILLIN (penicillin V potassium) is acid-stable and can be taken without regard to meals, but absorption is slightly improved on an empty stomach. It is first-line for group A streptococcal pharyngitis and to prevent rheumatic fever. Watch for hypersensitivity reactions; cross-reactivity with cephalosporins occurs in about 5-10% of cases. Adjust dose in severe renal impairment (CrCl <10 mL/min). |
| Patient Advice | Take this medication exactly as prescribed, even if you feel better. · Complete the full course of therapy to prevent resistance. · Report any rash, itching, or difficulty breathing immediately. · If you have diarrhea that is watery or bloody, stop taking and call your doctor. · Store at room temperature; reconstituted suspension must be refrigerated and discarded after 14 days. |