Inadvertent use of Bicillin C-R for treatment of syphilis--Maryland, 1998.

In October 1998, the Maryland Department of Health and Mental Hygiene (MDH) was notified that a public sexually transmitted disease (STD) clinic in a county (county A) had used a nonrecommended preparation to treat syphilis patients during January-October 1998. The clinic had been inadequately treating syphilis patients or syphilis contacts with Bicillin C-R (a mixture of 1.2 million units [MU] benzathine penicillin G [BPG] and 1.2 MU procaine penicillin G), rather than with Bicillin L-A (2.4 MU BPG). Compared with short-acting procaine penicillin G, BPG has a longer half-life considered essential for effective syphilis treatment because it yields sustained spirochetecidal levels needed to treat the slowly reproducing agent of syphilis, Treponema pallidum. The inadvertent use of Bicillin C-R, which contains only half the recommended dose of BPG for syphilis, was recognized by a health-care provider at the STD clinic in a neighboring county (county B) approximately 1 month after county B had borrowed BPG from county A. This report summarizes the investigation of the use of Bicillin C-R to treat STD patients in county A and discusses the frequency of Bicillin C-R use in STD clinics nationwide. Findings of this investigation indicate that inadvertent Bicillin C-R use is more frequent than previously known and that preventive measures should be taken to minimize such use.