UTICILLIN VK
Clinical safety rating: caution
Comprehensive clinical and safety monograph for UTICILLIN VK (UTICILLIN VK).
Uticillin VK (penicillin V potassium) is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs) in the bacterial cytoplasmic membrane, thereby inhibiting transpeptidation and autolysin inhibition, leading to cell lysis and death.
| Metabolism | Penicillin V is primarily metabolized by hydrolysis to penicilloic acid (inactive) via hepatic metabolism, with ~20-40% of the dose excreted unchanged in urine via renal tubular secretion and glomerular filtration. |
| Excretion | Renal: 70-80% unchanged via tubular secretion and glomerular filtration; biliary/fecal: minor (about 10%) |
| Half-life | 0.5-1.0 hour (prolonged in renal impairment; e.g., up to 10 hours in anuria) |
| Protein binding | 80% bound to serum albumin |
| Volume of Distribution | 0.3 L/kg (limited distribution; primarily extracellular fluid; low penetration into CNS, eyes, prostate) |
| Bioavailability | Oral: 60-70% (varies with food; bioavailability decreases when taken with meals) |
| Onset of Action | Oral: 30-60 minutes for peak serum concentration; clinical effect within 24 hours for susceptible infections |
| Duration of Action | 4-6 hours for susceptible bacteria; requires frequent dosing every 6 hours |
| Molecular Weight | 432.1 |
250-500 mg orally every 6-8 hours for 10 days for streptococcal pharyngitis; 250-500 mg orally every 6 hours for pneumococcal infections.
| Dosage form | TABLET |
| Renal impairment | CrCl 10-50 mL/min: same dose but every 8-12 hours; CrCl <10 mL/min: same dose but every 12-18 hours. |
| Liver impairment | No dosage adjustment required for mild to moderate hepatic impairment; caution in severe hepatic impairment due to potential accumulation. |
| Pediatric use | Weight <20 kg: 40-80 mg/kg/day orally divided every 6-8 hours; maximum 2 g/day. Weight ≥20 kg: 250-500 mg orally every 8 hours. |
| Geriatric use | No specific geriatric dose adjustments; monitor renal function and adjust based on CrCl as per renal adjustment guidelines. |
| 1st trimester | Penicillin VK is generally considered safe during the first trimester; animal studies have not shown risk, and there are no adequate human studies. |
| 2nd trimester | Safe; no known teratogenic effects in human studies. |
| 3rd trimester | Safe; use near term may theoretically affect neonatal flora, but no known adverse effects. |
Clinical note
Comprehensive clinical and safety monograph for UTICILLIN VK (UTICILLIN VK).
| Placental transfer | Penicillin VK crosses the placenta; peak cord blood levels approximately 50% of maternal serum levels. |
| Breastfeeding | Penicillin VK is excreted into breast milk in small amounts (about 0.1% of maternal dose). It is generally considered compatible with breastfeeding; however, monitor for potential rash, diarrhea, or candidiasis in the infant. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to penicillinsHypersensitivity to cephalosporins (cross-sensitivity)
| Precautions | Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) can occur; prior to therapy, inquire about previous hypersensitivity to penicillins, cephalosporins, or other allergens., Clostridium difficile-associated diarrhea (CDAD) ranging from mild diarrhea to fatal colitis; consider if diarrhea occurs during or after therapy., Use with caution in patients with renal impairment (reduce dose if CrCl < 10 mL/min)., Prolonged use may result in bacterial or fungal superinfection; monitor for signs of overgrowth., Avoid intravascular or intrathecal administration; for oral use only., Not effective against beta-lactamase-producing bacteria. |
| Food/Dietary | Food, especially acidic fruits and juices, can reduce absorption; administer at least 1 hour before or 2 hours after meals. |
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| Lactation Rating |
| L1 (Compatible) |
| Teratogenic Risk | Penicillin V, the active moiety of UTICILLIN VK (penicillin V potassium), is classified as FDA Pregnancy Category B. Animal reproduction studies have not demonstrated fetal risk, and adequate, well-controlled studies in pregnant women have not established teratogenic effects. However, fetal risks from therapeutic doses are considered low. First trimester exposure is not associated with major congenital malformations. Second and third trimester use has not shown increased fetal harm. Intrauterine exposure may theoretically alter fetal gut flora but clinical significance is unknown. |
| Fetal Monitoring | No specific maternal-fetal monitoring is required beyond standard prenatal care. Penicillin V is generally considered safe in pregnancy. Monitor maternal renal function if high doses or prolonged use is necessary. No fetal monitoring is routinely indicated. |
| Fertility Effects | No evidence suggests that penicillin V adversely affects human fertility. Animal studies have not demonstrated impairment of fertility. The drug has no known direct effects on gametogenesis, implantation, or early embryonic development. |
| Clinical Pearls | Penicillin V potassium is acid-stable and well absorbed orally, but food decreases absorption; take on an empty stomach. Renal dose adjustment needed for CrCl <10 mL/min. Not effective against beta-lactamase-producing organisms. Use with caution in patients with cephalosporin allergy due to cross-sensitivity (~10%). |
| Patient Advice | Take on an empty stomach (1 hour before or 2 hours after meals) with a full glass of water. · Complete the entire course even if you feel better. · Report any rash, diarrhea, or difficulty breathing to your healthcare provider immediately. · Store in a tight container at room temperature; do not refrigerate oral suspension. |