Benzathine penicillin G
A single deep IM injection for strep throat when adherence is uncertain, monthly rheumatic fever prophylaxis, and syphilis.
On this page
Uses
- Streptococcal pharyngitis (single dose).
- Secondary prevention of rheumatic fever (every 3–4 weeks).
- Syphilis.
Dose
| Indication | Dose |
|---|---|
| Strep throat, adult | 1.2 million units deep IM, single dose |
| Strep throat, child under 27 kg | 600,000 units deep IM, single dose |
| Rheumatic fever prophylaxis | 1.2 million units every 3–4 weeks (600,000 units if under 27 kg) |
| Early syphilis | 2.4 million units IM single dose |
Pregnancy and breastfeeding
Safe.
Side effects and cautions
- Painful injection; give deep IM into a large muscle, never IV.
- Penicillin allergy: anaphylaxis possible; observe after injection.
Frequently asked questions
How often is benzathine penicillin given for rheumatic fever?
Every 3–4 weeks, usually for years depending on the severity of heart involvement.
Used in these guides
Sources
Doses on this page are typical doses from the sources above. Always confirm with a current drug reference, the product leaflet and your hospital protocol, especially in children, pregnancy and kidney or liver disease.