Benzathine Penicillin G Treatment Guidelines

Primary Indications

The Centers for Disease Control and Prevention recommends benzathine penicillin G as the first-line treatment for syphilis at all stages (except neurosyphilis) and for group A streptococcal pharyngitis when single-dose intramuscular therapy is preferred 1, 2
For early syphilis, a single dose of 2.4 million units IM is the definitive treatment, applicable to primary syphilis, secondary syphilis, and early latent syphilis 2, 3
For late latent syphilis or syphilis of unknown duration, three doses of 2.4 million units IM at weekly intervals (total 7.2 million units) are necessary 4, 2
The Centers for Disease Control and Prevention recommends three doses of 2.4 million units IM at weekly intervals (total 7.2 million units) for tertiary syphilis (gummatous and cardiovascular) 4, 2
CSF examination should be performed before treatment to exclude neurosyphilis 4
Benzathine penicillin G should never be used for neurosyphilis—aqueous crystalline penicillin G IV is required for CNS disease 4, 2

For pregnant women, penicillin is the only proven effective therapy for preventing congenital syphilis 2
Pregnant women with penicillin allergy must undergo desensitization followed by penicillin treatment 2, 3
The Centers for Disease Control and Prevention recommends that pregnant women with penicillin allergy should not substitute with alternatives in pregnancy—only penicillin prevents congenital transmission 2

Quantitative nontreponemal tests (RPR or VDRL) should be performed at 6 and 12 months for primary/secondary syphilis 2
For latent syphilis, tests should be repeated at 6, 12, and 24 months 2
The expected response is a fourfold decline in titer within 6 months for early syphilis, 12-24 months for late syphilis 2, 3

For adults and adolescents, 1.2 million units IM as a single dose is recommended when single-dose therapy is preferred 1
For children weighing <27 kg, 600,000 units IM as a single dose is recommended when single-dose therapy is preferred 1
The American Academy of Pediatrics recommends that this is particularly valuable when compliance with 10-day oral therapy is uncertain 1

For infants meeting specific criteria, 50,000 units/kg IM as a single dose is recommended 5, 6
For older children with acquired syphilis, 50,000 units/kg IM (up to adult dose of 2.4 million units) as a single dose for early syphilis is recommended 2
For late latent syphilis in children, 50,000 units/kg IM for three doses at weekly intervals (up to adult total of 7.2 million units) is recommended 2

For early syphilis, doxycycline 100 mg orally twice daily for 14 days is recommended 2, 3
For late latent syphilis, doxycycline 100 mg orally twice daily for 28 days is recommended 4, 2
The Infectious Diseases Society of America recommends that these alternatives have not been proven to prevent rheumatic fever or congenital syphilis 1

The Centers for Disease Control and Prevention recommends benzathine penicillin G dosed at 50,000 units/kg IM (up to adult dose of 2.4 million units) for infants and children, with the option to dilute with local anesthetics to reduce pain, as supported by the MMWR Recommendations and Reports 7, 8, 9

For pediatric patients weighing over 27 kg, the American Academy of Family Physicians recommends a dose of 1,200,000 units as a standard dose for streptococcal infections and streptococcal pharyngitis 10
The Infectious Diseases Society of America strongly recommends a single dose of 1,200,000 units IM for streptococcal pharyngitis, with high-quality evidence 10
For patients with syphilis, the Centers for Disease Control and Prevention recommends 50,000 U/kg (maximum 2,400,000 units) in a single dose, which would be 2,400,000 units for a 62 kg patient 11, 12

The specific indication determines the dosage, with streptococcal pharyngitis typically requiring 1,200,000 units and syphilis requiring up to 2,400,000 units 10, 11, 12
It is essential to verify the specific indication before prescribing, as syphilis may require a higher dose than streptococcal pharyngitis 10, 11, 12