Effective March 15, 2024, benzathine benzylpenicillin (Extencilline^®) has been added to the ADAP and PrEP-AP formularies.

To address the extended shortage of long-acting benzathine penicillin G (Bicillin^® L-A) with supplies now estimated to not recover until the fourth quarter of 2024, the United States Food and Drug Administration (FDA) has temporarily authorized the use of Extencilline^® (benzathine benzylpenicillin injection, powder, for suspension) for treatment of syphilis. Extencilline^® has been determined to be therapeutically equivalent to Bicillin^® L-A and is currently authorized and marketed in other countries for the treatment of syphilis. The FDA has provided distribution and administration information as the preparation and administration of Extencilline^® differs from Bicillin^® L‑A. With the extended Bicillin^® L-A shortage, the California Department of Public Health (CDPH) recommends the continued prioritization of Bicillin^® L-A for pregnant people with syphilis and infants exposed to syphilis in utero, and the use of other alternative regimens, with treatment considerations (PDF), for non-pregnant adults. In the case that Bicillin^® L-A becomes unavailable, Extencilline^® can be used for the treatment of syphilis – please see the CDPH Dear Colleague Letter dated January 26, 2024 (PDF) for more information.

ADAP management requests that you share this information with your clinical leadership team and local prescribers. The ADAP drug formulary and Pr​EP-AP drug formulary (PDF) have been updated to reflect the addition of benzathine benzylpenicillin (Extencilline^®).

If you have any questions regarding the addition of these medications to the ADAP formulary, please contact the OA Formulary Specialist, James Vo (James.Vo@cdph.ca.gov).

Thank you,