Penicillin V
PEN-VEE K
What it isOral penicillin V that inhibits bacterial penicillin-binding proteins; streptococcal pharyngitis and rheumatic-fever prophylaxis.
Why this oneGroup A streptococcus remains susceptible, keeping this narrow-spectrum drug first-line for strep throat.
What limits itRenal accumulation or high exposure can antagonize GABA-A and provoke seizures; allergy and absent staphylococcal coverage also matter.
FDA-approved for
- streptococcal infections (1945)
- syphilis (1945)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Streptococcal (URI, scarlet fever, erysipelas), mild-moderate | >=12 yr | 125-250 mg q6-8h | ||
| Pneumococcal (respiratory incl. otitis media), mild-moderate | >=12 yr | 250-500 mg q6h until afebrile >=2 days | ||
| Staphylococcal skin/soft tissue, mild | >=12 yr | 250-500 mg q6-8h | ||
| Fusospirochetosis (Vincent's), oropharynx | >=12 yr | 250-500 mg q6-8h | ||
| Rheumatic fever/chorea recurrence prophylaxis | >=12 yr | 125-250 mg BID (continuing) | ||
| Bacterial endocarditis prophylaxis (dental/URI procedures) | adult | 2 g 1 h before procedure, then 1 g 6 h later | ||
| Bacterial endocarditis prophylaxis (children <60 lb) | pediatric | 1 g 1 h before, then 500 mg 6 h later |
Renal Undefined
Hepatic Undefined
Instructions
- Dose per organism sensitivity and infection severity; adjust to clinical response
- Continue streptococcal therapy for at least 10 days to reduce rheumatic fever risk
Contraindications
- Prior hypersensitivity reaction to any penicillin
Cautions
- Serious, occasionally fatal hypersensitivity (anaphylaxis) can occur, including in patients with prior penicillin/cephalosporin sensitivity
Adverse reactions
- Nausea, vomiting, epigastric distress, diarrhea, black hairy tongue
- Hypersensitivity: rash (maculopapular to exfoliative), urticaria, serum-sickness-like reactions, laryngeal edema, anaphylaxis
- Fever and eosinophilia
- Rarely: hemolytic anemia, leukopenia, thrombocytopenia, neuropathy, nephropathy
Pregnancy Undefined
Lactation Undefined
NO BOXED WARNINGS
Principal riskSeizures at high dose or in renal failure; no staphylococcal cover
Cost, est. cash$5–$150/month
Generic entry1988
Classes and tags
Clinical profile
Legacy pregnancy categoryB
Defining liabilityAllergy, gastrointestinal effects and agent-specific renal, hepatic, hematologic or interaction risks.
Mechanism of action: Penicillin V ballicule
Open Penicillin V in the interactive console ↗
Memory aids: mascots and interaction avatars
