Renal failure developed after a prolonged course of vancomycin therapy in 2 patients who were receiving tenofovir disoproxil fumarate as part of an antiretroviral regimen. Tenofovir has been implicated in the development of Fanconi syndrome and renal insufficiency because of its effects on the proximal renal tubule. Vancomycin nephrotoxicity is infrequent but may result from coadministration with a nephrotoxic agent. Clinicians should be aware that tenofovir may raise the risk of renal failure during prolonged administration of vancomycin.
We present a patient with fully controlled HIV disease and a normal CD4 count whose initial treatment for syphilis failed. Biopsy-proven syphilitic colitis and severe gastroparesis developed, requiring the insertion of a temporary percutaneous gastrostomy tube. The patient responded to a course of high-dose aqueous crystalline penicillin followed by doxycycline, and he completely recovered. The occurrence of failure of conventional syphilis treatment in HIV-infected patients is discussed.

