Phenoxymethylpenicillin

Penicillin V·Infectious Diseases - Penicillins

Strep tonsillitis, erysipelas, prevention of rheumatic fever, post-splenectomy pneumococcal prophylaxis

PBSBETA-LACTAMCilicaine VK, Abbocillin-VK250 mg tabletS4+1

Max Dose

3 g/day

Half-life

1 h

Food

DECREASES ABSORPTION

Anaphylaxis

CRITICAL

Rapid Summary

Overview

Narrow-spectrum oral penicillin (Pen V). The absolute drug of choice for exquisitely sensitive Streptococcus pyogenes (Group A Strep).

Maximum Dose

Max 3 g/day (e.g., 500 mg q4h to q6h in severe infections).

Clinical Focus

Has very poor oral bioavailability compared to Amoxicillin. Must be taken strictly on an empty stomach to achieve therapeutic blood levels.

Bottom Line

Phenoxymethylpenicillin is the narrow-spectrum oral penicillin for streptococcal pharyngitis and rheumatic fever prophylaxis, but must be taken on an empty stomach and has limited gram-negative coverage.

Formulation & Access

Brand Names

Cilicaine VK, Abbocillin-VK

Oral Routes

Tablets/Capsules (250 mg, 500 mg). Oral liquid (125 mg/5mL, 250 mg/5mL).

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

Strep tonsillitis, erysipelas, prevention of rheumatic fever, post-splenectomy pneumococcal prophylaxis.

Clinical Place

Highly targeted, narrow-spectrum agent. Does NOT cover Gram-negatives or Staphylococcus aureus (unless proven sensitive).

Quick reference

Class & Role

Penicillin V — Narrow-spectrum oral penicillin (Pen V).

Route / Formulation

Tablets/Capsules (250 mg, 500 mg). Oral liquid (125 mg/5mL, 250 mg/5mL). (Cilicaine VK, Abbocillin-VK)

Usual Dose & Max

PO 500 mg BD for 10 days (to eradicate carriage and prevent Rheumatic Fever). Max 3 g/day (e.g., 500 mg q4h to q6h in severe infections).

Key Indication Doses

Streptococcal Tonsillitis: PO 500 mg BD for 10 days (to eradicate carriage and prevent Rheumatic Fever). Mild Cellulitis (Erysipelas): PO 500 mg QID. Rheumatic Fever Prophylaxis: PO 250 mg BD (Often continued for years).

Best Uses

Avoid / Cautions

History of Type 1 (IgE) penicillin hypersensitivity. Pregnancy Category A.

Key Risks

Immunological: IgE-mediated anaphylaxis, angioedema. MODERATE — Non-allergic maculopapular rash. Gastrointestinal: Nausea, diarrhea (but lower C. diff risk than broad-spectrum agents).

Key Interactions

Food drops absorption by up to 50%. Must take 1 hour before or 2 hours after meals. Probenecid blocks renal excretion, doubling blood levels.

Monitoring

Ensure strict adherence to the 10-day course for tonsillitis to prevent acute rheumatic fever and glomerulonephritis. No specific routine laboratory tests required.

Clinical Pearl

Because it must be taken QID on an empty stomach for skin infections, compliance is historically terrible. If the patient is likely to fail this, switch to Amoxicillin (TDS, food independent) or Cephalexin.

Access

Cilicaine VK, Abbocillin-VK250 mg tablet

Brand: Cilicaine VK, Abbocillin-VK
Formulation: Tablets/Capsules (250 mg, 500 mg)