LEDERCILLIN VK
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LEDERCILLIN VK (LEDERCILLIN VK).
Penicillin V is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis and death. It is bactericidal against susceptible organisms during the active growth phase.
| Metabolism | Penicillin V is primarily metabolized in the liver to penicilloic acid, which is inactive. Approximately 20-40% of the dose is metabolized; the remainder is excreted unchanged in urine. |
| Excretion | Renal elimination predominantly via tubular secretion of unchanged drug (>90% of absorbed dose). Approximately 20-40% of an oral dose is recovered in urine as unchanged penicillin V. Biliary excretion accounts for <1% of elimination; fecal elimination is negligible. |
| Half-life | Terminal elimination half-life is 0.5 hours (range 0.4–0.6 hours) in adults with normal renal function. In severe renal impairment (CrCl <10 mL/min), half-life extends to ~4 hours. |
| Protein binding | Approximately 60–80% bound to serum albumin. |
| Volume of Distribution | Volume of distribution is approximately 0.17–0.3 L/kg; low Vd reflects limited tissue penetration, consistent with a hydrophilic drug that remains primarily in extracellular fluid. |
| Bioavailability | Oral bioavailability is 60–73% under fasting conditions; food decreases absorption by 25–50%, reducing peak concentrations by up to 50%. |
| Onset of Action | Oral: Peak serum concentrations occur at 0.5–1 hour after administration (fasting). Onset of antibacterial effect is rapid, typically within 1–2 hours for susceptible organisms. |
| Duration of Action | Duration of therapeutic concentrations is approximately 4–6 hours after a single oral dose. For treatment of streptococcal pharyngitis, 10-day regimen is standard to ensure eradication. |
| 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 | GFR 10-50 mL/min: administer every 8-12 hours; GFR <10 mL/min: administer every 12-18 hours. |
| Liver impairment | No adjustment required for mild to moderate hepatic impairment; use with caution in severe hepatic impairment (Child-Pugh class C) due to potential for accumulation, but no specific guidelines exist. |
| Pediatric use | Children >12 years: 250-500 mg orally every 6 hours; Children <12 years: 25-50 mg/kg/day orally in divided doses every 6 hours; maximum 3 g/day. |
| Geriatric use | Dose adjustment based on renal function; monitor for superinfection and adverse effects; consider age-related decline in renal function; no specific dose reduction if renal function normal. |
| 1st trimester | Penicillin VK is generally considered safe in the first trimester. Animal studies have not shown fetal risk, and there are no adequate human studies, but potential benefits may warrant use. |
| 2nd trimester | Penicillin VK is generally considered safe in the second trimester. No known fetal risk. |
| 3rd trimester | Penicillin VK is generally considered safe in the third trimester. No known fetal risk. |
Clinical note
Comprehensive clinical and safety monograph for LEDERCILLIN VK (LEDERCILLIN VK).
| Placental transfer | Penicillin VK crosses the placenta to a limited extent, achieving low fetal concentrations. It is classified as FDA Pregnancy Category B, indicating no evidence of risk in animal studies but no adequate human studies. |
| Breastfeeding | Penicillin VK is excreted into breast milk in low amounts. It is considered compatible with breastfeeding, but caution is advised in infants with penicillin allergy or potential for alteration of gut flora. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to penicillinsHypersensitivity to any component of the formulation
| Precautions | Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) have occurred, more frequently in patients with penicillin allergy history., Patients with a history of severe hypersensitivity to cephalosporins or other beta-lactams should be monitored., Use with caution in patients with renal impairment; dose adjustment may be necessary., Prolonged use may result in overgrowth of non-susceptible organisms (e.g., Clostridioides difficile-associated diarrhea)., Hematologic reactions, including leukopenia and thrombocytopenia, have been reported with prolonged therapy. |
| Food/Dietary | Food reduces absorption; avoid taking with meals. No specific food-drug interactions. |
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| Lactation Rating | L1 - Safe |
| Teratogenic Risk | Penicillin VK (phenoxymethylpenicillin) is classified as FDA pregnancy category B. Animal reproduction studies have not demonstrated fetal risk, and there are no adequate well-controlled studies in pregnant women. However, penicillins are generally considered safe during pregnancy. No known teratogenic effects have been reported in first trimester; third trimester use associated with altered gut flora but no direct fetal harm. |
| Fetal Monitoring | No specific routine monitoring required beyond standard prenatal care. Monitor for signs of allergic reaction (rash, urticaria) and gastrointestinal symptoms. In prolonged therapy, monitor renal and hepatic function. No fetal monitoring indicated for short-term use. |
| Fertility Effects | There are no known adverse effects on fertility in either males or females based on available data. Penicillins do not interfere with spermatogenesis or ovulation. |
| Clinical Pearls | Penicillin V potassium is acid-stable and well absorbed orally; administer on an empty stomach (1 hour before or 2 hours after meals) to maximize absorption. Use primarily for streptococcal pharyngitis, mild to moderate upper respiratory tract infections, and prophylaxis of rheumatic fever. Not effective against beta-lactamase-producing organisms. Monitor for hypersensitivity reactions; cross-allergy with cephalosporins possible. |
| Patient Advice | Take this medication exactly as prescribed, even if you feel better. · Take on an empty stomach—at least 1 hour before or 2 hours after meals for best absorption. · Complete the full course of therapy to prevent resistance and recurrence. · Report any signs of allergic reaction (rash, hives, difficulty breathing) to your doctor immediately. · Store at room temperature, away from moisture and heat. |