PEN-VEE K
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PEN-VEE K (PEN-VEE K).
Penicillin V binds to penicillin-binding proteins (PBPs) located on the bacterial cell wall, inhibiting the final transpeptidation step of peptidoglycan synthesis, leading to cell lysis.
| Metabolism | Primarily metabolized by hydrolysis to penicilloic acid; minor hepatic metabolism. |
| Excretion | Renal excretion of unchanged drug via glomerular filtration and tubular secretion accounts for 60-90% of elimination; biliary/fecal elimination is minimal (<10%). |
| Half-life | Terminal elimination half-life: 30-60 minutes in adults with normal renal function, prolonged to 3-10 hours in severe renal impairment. |
| Protein binding | Approximately 60% bound to serum albumin, primarily to albumin. |
| Volume of Distribution | Volume of distribution: 0.3-0.4 L/kg, reflecting limited distribution into extracellular fluid; low penetration into CSF except with inflamed meninges. |
| Bioavailability | Oral bioavailability: 60-73% (variable due to gastric acid degradation and food interference). |
| Onset of Action | Oral administration: onset of action within 30-60 minutes for susceptible organisms. |
| Duration of Action | Duration of action: 4-6 hours for oral dosing, necessitating frequent administration every 6-8 hours for continuous bactericidal effect. |
| Molecular Weight | 388.48 |
250-500 mg orally every 6-8 hours for mild to moderate infections; up to 2 g/day for severe infections.
| Dosage form | FOR SOLUTION |
| Renal impairment | CrCl 10-50 mL/min: administer every 8-12 hours; CrCl <10 mL/min: administer every 12-18 hours. |
| Liver impairment | No adjustment required for mild to moderate hepatic impairment (Child-Pugh A/B). For severe impairment (Child-Pugh C), consider dose reduction by 25-50% due to potential accumulation. |
| Pediatric use | Children >12 years: same as adult dosing. Children 1 month to 12 years: 25-50 mg/kg/day divided every 6-8 hours. Infants <1 month: 20-30 mg/kg/day divided every 12 hours. |
| Geriatric use | No specific dose adjustment besides renal function adjustments. Monitor for renal impairment and adjust dose per creatinine clearance. Increased risk of adverse effects (e.g., rash, diarrhea) due to age-related changes. |
| 1st trimester | Generally considered safe; no evidence of teratogenicity in humans. Use if clearly needed. |
| 2nd trimester | Safe; used for treatment of syphilis and other infections during pregnancy. |
| 3rd trimester | Safe; no known fetal harm. |
Clinical note
Comprehensive clinical and safety monograph for PEN-VEE K (PEN-VEE K).
| Placental transfer | Penicillin V crosses the placenta, but fetal serum levels are low relative to maternal levels. |
| Breastfeeding | Penicillin V is excreted into breast milk in small amounts; usually compatible with breastfeeding. For serious infections, consider alternative or monitor infant for diarrhea, rash, or sensitization. |
| Lactation Rating |
■ FDA Black Box Warning
No FDA boxed warning
| Serious Effects |
Hypersensitivity to penicillin or any component of the formulation
| Precautions | Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) can occur, Prolonged use may result in bacterial or fungal superinfection, Use with caution in patients with renal impairment (dose adjustment may be needed), Risk of Clostridioides difficile-associated diarrhea |
| Food/Dietary | Avoid grapefruit juice. High-fat meals may reduce absorption. No other significant food interactions. |
| Clinical Pearls |
Loading safety data…
| L1 (Safe) |
| Teratogenic Risk | Penicillin V potassium (PEN-VEE 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. Based on available data, there is no evidence of teratogenicity in the first trimester, and no increased risk of fetal malformations has been observed. In the second and third trimesters, the drug is considered low risk. The drug crosses the placenta, but therapeutic concentrations are not associated with adverse fetal effects. |
| Fetal Monitoring | Standard maternal monitoring includes assessment for signs of hypersensitivity reactions (rash, urticaria, anaphylaxis) and gastrointestinal side effects. No specific fetal monitoring is required, but routine prenatal care should continue. In cases of high-dose therapy or prolonged use, monitoring for superinfection or Clostridium difficile-associated diarrhea is recommended. |
| Fertility Effects | There is no evidence indicating that penicillin V potassium has any adverse effect on fertility in males or females. Animal studies have not reported impaired fertility. Clinically, penicillins are not known to influence reproductive function. |
| Penicillin V potassium (Pen-Vee K) is a narrow-spectrum penicillinase-labile penicillin. It is acid-stable and can be taken with or without food, but absorption may be slightly decreased with food. It is the drug of choice for streptococcal pharyngitis and for prophylaxis of rheumatic fever. Ensure complete course to prevent resistance. Not effective against beta-lactamase-producing organisms. |
| Patient Advice | Take this medication exactly as prescribed for the full duration, even if symptoms improve. · You may take it with or without food, but taking it on an empty stomach may increase absorption. · Shake the oral suspension well before each dose. · Do not take with grapefruit juice as it may affect absorption. · Report any signs of allergic reaction (rash, itching, swelling, difficulty breathing) or severe diarrhea. · Avoid alcohol while on this medication to prevent side effects. |