Treatment of infection: 0.3 to 1.2 million units repeated every five to seven days.
Prophylaxis of rheumatic fever: 1.2 million units every three weeks.
Specific dosage schedule: Treatment of group-A β-haemolytic streptococcal infections: A single intramuscular dose of 600,000 units.
Prevention of rheumatic fever: Monthly injection of a single dose of 1.2 million units is the most effective regimen for preventing further attacks of rheumatic fever.
Treatment of acute otitis media: A single injection of 6 million units.
- Early syphilis- 2.4 million units as a single dose.
- Late syphilis: 2.4 million units weekly for three successive weeks.
- Neurosyphilis: Benzylpenicillin, intravenously, 2 to 4 million units every 4 hours for 10 days, followed by benzathine penicillin intramuscularly, 2.4 million units weekly for three successive weeks.
- Congenital syphilis: Asymptomatic infants with normal cerebrospinal fluid, intramuscularly 50,000 units per kg in a single dose.
Primary and secondary syphilis have been treated with single injections of 2.4 million units of long acting benzathine penicillin (Benzapen) weekly for 2 to 4 weeks with satisfactory results.