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Syphilis Treatment Guide for Doctors

For more information on syphilis, refer to the Canadian Sexually Transmitted Infections Guidelines.

Order resource guidelines.

Recommended Regimens

Primary, secondary, early latent, less than one year duration:

  • Bicillin* L-A (Penicillin G benzathine) 2.4 million U IM in a single dose (each injection contains 1.2 million U IM)

Late latent more than one year of indeterminate duration:

  • Bicillin* L-A (Penicillin G benzathine) 2.4 million U IM once a week for three consecutive weeks (total dose 7.2 million U IM)

Call the Sexual Health Centre to obtain Bicillin* L-A (Penicillin G benzathine).

During Pregnancy

Same as recommended treatment regimen. If a pregnant woman is treated with anything other than Bicillin* L-A (Penicillin G benzathine) or is treated in the last month of pregnancy, the baby must be treated after birth.

For consult on syphilis infection during pregnancy, call 905-688-3817 or 1-800-263-5757 (Monday - Friday, 8:30 a.m. - 4:30 p.m.) and request to speak to a nurse.

Penicillin Allergy

Desensitization and use of penicillin preferred.

Primary, secondary, early latent

  • Docycline 100 mg orally bid for 14 days

Late latent


For primary, secondary, early latent

  • Repeat serology three, six and 12 months after treatment

For late latent

  • Repeat serology 12 months after treatment

Free treatment for reportable Sexually Transmitted Infections are available from our Sexual Health Centres.

¹ Pichichero, M.E., 2005, A review of evidence supporting the American academy of pediatrics recommendation for prescribing cephalosporin antibiotics. American Academy of Pediatrics. 115(4), 1048-1057. Anti-infective guidelines for community acquired infections, 2010.

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