Narrow-spectrum penicillin (Penicillin V)
Phenoxymethylpenicillin
Adult dose
Dose: 500mg PO QDS, 5–10 days. Tonsillitis (Strep): 500mg–1g QDS for 10 days
Route: PO
Frequency: QDS
Paediatric dose
Dose: 12.5 mg/kg
Route: PO
Frequency: QDS
Age bands
- 0–12m: 62.5mg QDS
- 12–60m: 125mg QDS
- 60–216m: 250mg QDS
Dose adjustments
Renal
Reduce in severe renal impairment
Paediatric weight-based calculator
Clinical pearls
- Streptococcal tonsillitis, rheumatic fever prophylaxis, post-splenectomy prophylaxis
- Take 1h before or 2h after food
Contraindications
- Penicillin allergy
Side effects
- Diarrhoea
- Rash
- Hypersensitivity (incl. anaphylaxis)
- C. difficile infection
Interactions
- Methotrexate
- Warfarin (variable)
- Probenecid
Monitoring
- Symptoms
- Allergy
Reference: BNFc; BNF; NICE NG84/NG109; https://bnf.nice.org.uk/drugs/phenoxymethylpenicillin/. Verify against your local formulary and the latest BNF before prescribing.
Related
Curated clinical cross-links plus same-class fallbacks.
Calculators
Pathways
- Infective Endocarditis · ESC 2023 Infective Endocarditis Guidelines; NICE NG41
- Eczema Herpeticum · BAD; NICE CKS
- Suspected Bacterial Meningitis (Adult) · NICE NG240 (2024); NICE NG143 (paeds)
- Clostridioides difficile Colitis · NICE NG199 (2021); IDSA/SHEA 2021
- Returning Traveller — Fever · NaTHNaC; PHE; ESCMID 2018
- Malaria — Diagnosis & Management · PHE 2016; WHO 2023