Intravenous treatment of fibromyalgia with the 5-HT3 receptor antagonist tropisetron in a rheumatological practice.

In 223 fibromyalgia (FM) patients in a rheumatology practice, a follow-up postal survey was carried out 0.5-2 years after a 5-day intravenous (i.v.) treatment with 5 mg of the 5-HT3 receptor antagonist tropisetron daily on the effect of this treatment. 121 patients returned the completed questionnaire. After subtraction of 22 undeliverable questionnaires, this represented 60.2% of patients contacted for whom an assessment of the tropisetron treatment was possible. A good to very good effect of the treatment on the pain was reported by 45% of the patients, and only 25% reported an unsatisfactory effect. The effect of tropisetron IV lasted between one day and 12 weeks (mean 8.6 +/- 13.6 d). Sleep and general condition were also assessed as good or very good by almost half of the patients. The tolerance of tropisetron was generally good. In comparison with the current treatment and the best treatment with other drugs ever received, tropisetron was rated as more efficacious in almost half of the cases, though an unsatisfactory effect of tropisetron compared to other treatments was reported in 30% of the cases. Considered in comparison to less or at most equally efficacious alternatives, according to this open respective study, IV tropisetron treatment represents a promising option for the treatment of FM even though the study design incorporated many imponderables. Particularly the question of whether the success of treatment can be improved further with a longer lasting treatment or a selection of the patients still needs to be settled.