Oral penicillin indicated for mild to moderately severe infections due to susceptible organisms, including streptococcal pharyngitis, rheumatic fever prophylaxis and odontogenic infections.
Also known as: Penicilina V, Fenoximetilpenicilina
DailyMed approved label (Penicillin V Potassium Tablet; setID 64ac283c-fe6a-49f0-ae85-90ab98e38272).
DailyMed approved label (Penicillin V Potassium Tablet; setID 64ac283c-fe6a-49f0-ae85-90ab98e38272).
Phenoxymethylpenicillin + probenecid: probenecid inhibits penicillin tubular secretion — raises serum concentrations.
The Prontuário Terapêutico documents in the phenoxymethylpenicillin monograph (1.1.1.1): "Probenecid competitively inhibits the tubular secretion of penicillins, causing a significant increase in their serum concentrations". Historically, probenecid was used as an adjuvant to prolong serum penicillin levels (including in syphilis and gonorrhoea treatment), but this practice is now reserved for specific indications and should not be done routinely. The raised concentrations may potentiate dose-dependent adverse effects of penicillins (neurotoxicity at high doses, more intense allergic reactions). The practical guidance is to avoid the combination routinely; if probenecid is used as an adjuvant for a specific indication, monitor for signs of toxicity and adjust the penicillin dose.
Phenoxymethylpenicillin + probenecid: probenecid inhibits penicillin tubular secretion — raises serum concentrations.
The Prontuário Terapêutico documents in the phenoxymethylpenicillin monograph (1.1.1.1): "Probenecid competitively inhibits the tubular secretion of penicillins, causing a significant increase in their serum concentrations". Historically probenecid was used as an adjuvant to prolong penicillin levels — today the combination is not routinely recommended.
Monitor for signs of toxicity if the combination is used.
Increased adverse effects with the combination.
Avoid routine combination; if probenecid is used as an adjuvant (e.g., specific indications), monitor for toxicity.
Prontuário Terapêutico do INFARMED (11th ed., 2012) — Phenoxymethylpenicillin, 1.1.1.1 ; approved Probenecid label (MARLEX): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5d552de5-2d18-4464-bcaf-0311fa3f080d
Phenoxymethylpenicillin absorption is reduced when taken with food; taking on an empty stomach is recommended.
Take 1 hour before or 2 hours after meals.
DailyMed/FDA (NIH/NLM) — approved Penicillin V Potassium label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=64ac283c-fe6a-49f0-ae85-90ab98e38272
No relevant pharmacokinetic interaction; usual moderation during treatment.
Moderate alcohol intake.
DailyMed/FDA (NIH/NLM) — approved Penicillin V Potassium label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=64ac283c-fe6a-49f0-ae85-90ab98e38272
Phenoxymethylpenicillin is contraindicated in patients with documented penicillin allergy (risk of anaphylaxis).
Confirm allergy history before prescribing.
DailyMed/FDA (NIH/NLM) — approved Penicillin V Potassium label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=64ac283c-fe6a-49f0-ae85-90ab98e38272
Phenoxymethylpenicillin elimination is reduced in severe renal impairment, with a risk of accumulation.
Adjust the interval in severe renal impairment.
DailyMed/FDA (NIH/NLM) — approved Penicillin V Potassium label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=64ac283c-fe6a-49f0-ae85-90ab98e38272
Penicillins are considered safe in pregnancy.
May be used in any trimester when indicated.
Present in breast milk in small amounts; compatible with breastfeeding.
No specific contraception required.
DailyMed/FDA (NIH/NLM) — approved Penicillin V Potassium label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=64ac283c-fe6a-49f0-ae85-90ab98e38272
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Bactericidal antibiotic that acts against sensitive microorganisms during active multiplication by inhibiting biosynthesis of cell-wall mucopeptide.
Inhibition of bacterial cell-wall synthesis (PBP binding); inactive against penicillinase-producing bacteria (many staphylococcal strains).
Penicillin V potassium is more resistant to gastric-acid inactivation than penicillin G; it may be given with meals, though blood levels are slightly higher when fasting. Average levels 2–5x higher than oral penicillin G.
Rapid renal excretion; only ~25% of the oral dose is recovered in urine, reflecting partial absorption.
Short half-life (~30 min); requires repeated administration throughout the day to maintain effective levels.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
