Treatment failure of vaginal trichomoniasis in clinical practice.

We have conducted a retrospective study of treatment failure of Trichomonas vaginalis (TV) infection in a busy, urban genitourinary medicine clinic in Birmingham, UK, between 1998 and 2002. The prevalence of non-response to standard doses of metronidazole without any history of reinfection or nonadherence was 1.7% (28/1603) overall, and has significantly increased from 0.38% in 1999 to 3.5% in 2002 (P = 0.001, chi2 test). There were no associated demographic factors. The majority of patients (53% or 15/28) responded to either a repeat of standard (10/26) or higher oral dose (5/7) of metronidazole. A standardized treatment algorithm using a high dose of metronidazole may be useful in the absence of any new, efficacious non-imidazole-based TV therapy in the clinical management of persistent TV infection.