Treponemicidal levels of amoxicillin can be achieved in cerebrospinal fluid following oral treatment with only 4 g amoxicillin and 2 g probenecid daily in late stage syphilis

摘要

Sirs: The British Association for Sexual Health and HIV (BASHH) guideline1 for management of syphilis still indicate that parenteral daily injections are the treatment of choice to achieve treponemicidal levels in the cerebrospinal fluid (CSF). Some of the referenced studies indicated that oral treatment could achieve these levels; one for example using doses of 6 g of amoxicillin daily.2 In the 1980s, although syphilis had almost disappeared from Liverpool, we had set up a study looking at drug levels in CSF. Our study used oral amoxicillin 4 g and probenecid 2 g daily in divided doses for between 15 and 21 days. Ethical Committee approval was obtained for the study and all patients gave informed consent. Eight consecutive patients - five with syphilitic deafness (4 of whom were congenital), one with syphilitic chorioretinitis, one with tabes dorsalis and one with latent sero-resistant syphilis were enrolled. As these patients needed lumbar puncture anyway for their clinical management we were able to commence treatment first and then do the lumbar puncture. Trough levels of CSF and serum amoxicillin levels were measured on day 4 or 6 of treatment between three and six hours after the last amoxicillin dose using a microbiological assay. One patient developed gastrointestinal side-effects severe enough to warrant cessation of oral antibiotics.