What is the recommended dose of penicillin (Penicillin G) for treating syphilis in pregnancy?

From the Guidelines

For pregnant patients with syphilis, the recommended treatment is benzathine penicillin G 2.4 million units administered intramuscularly as a single dose, as it is the only proven effective therapy for syphilis during pregnancy, effectively treating the infection in both the mother and preventing congenital syphilis in the fetus 1.

Key Considerations

• The treatment regimen for late latent syphilis or syphilis of unknown duration is benzathine penicillin G 2.4 million units intramuscularly once weekly for three consecutive weeks (7.2 million units total) 1.
• If the patient has a penicillin allergy, desensitization is recommended rather than using alternative antibiotics, since penicillin remains the gold standard treatment 1.
• Patients should be monitored with follow-up serologic testing at 1,3,6, and 12 months after treatment to ensure adequate response.
• Treatment should be initiated promptly upon diagnosis, regardless of the pregnancy stage, to minimize complications for both mother and baby.

Important Notes

• Alternative antibiotics have limited evidence for efficacy and safety in pregnancy, making penicillin the preferred treatment option 1.
• The Centers for Disease Control and Prevention (CDC) updates treatment guidelines regularly, and clinicians should access the CDC website for the most up-to-date information 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION ... Syphilis Primary, secondary, and latent—2,400,000 units (1 dose). The recommended dose of penicillin G for treating syphilis in pregnancy is 2,400,000 units (1 dose), as the drug label does not provide specific dosage recommendations for pregnant women that differ from the general recommendations for syphilis treatment 2.

From the Research

Recommended Dose of Penicillin for Treating Syphilis in Pregnancy

• The recommended treatment for syphilis in pregnancy is benzathine penicillin G, as evidence of decreased risk of congenital syphilis with other modalities is lacking 3.
• The dose of benzathine penicillin G for treating syphilis in pregnancy is not explicitly stated in the provided studies, but a single intramuscular injection of 2.4 million U of benzathine penicillin G is reported to have 90% to 100% treatment success rates for early syphilis 4.
• For pregnant women, penicillin remains the only effective treatment option, and if these patients are allergic to penicillin, desensitization is required before treatment is initiated 5.
• Guidelines from around the world recommend benzathine penicillin G as the first-line therapy for syphilis in pregnancy, consistent with World Health Organization (WHO) guidelines 6.
• Missed doses of penicillin are not acceptable for pregnant women, highlighting the importance of strict adherence to the treatment regimen 7.

Key Considerations

• Congenital syphilis can lead to stillbirth, miscarriage, preterm birth, birth defects, and lifelong physical or neurologic changes, making prompt and effective treatment crucial 3.
• The diagnosis of syphilis in pregnancy involves testing, including either the reverse-sequence algorithm or the traditional algorithm, and determination of the clinical stage of syphilis 3.
• Serial cerebrospinal fluid examinations are necessary to ensure adequate treatment of neurosyphilis, and a cerebrospinal fluid examination to diagnose neurosyphilis is recommended in certain cases 5, 7.