Treatment of fibromyalgia with intravenous application of tropisetron

Objective: As in a prospective, randomized, placebo-controlled, multicenter , double-blind trial in fibromyalgia [FMS] a significant reduction of pain especially, but of other symptoms as well, could be gained after 10 days of peroral daily treatment with 5 mg tropisetron, the question was evaluated as to whether quicker and better effects could be achieved with intravenous application of 2 mg tropisetron daily for a limited period of time. Methods: In the first cohort, 18 FMS patients received a single bolus intra venous [i.v.] injection of 2 mg tropisetron, in the second cohort 24 FMS pa tients were treated with 2 mg i.v. bolus injection tropisetron daily for fi ve days. Pain intensity was measured with the visual analog scale and the p ainscore; pain at the tenderpoints and control points [dolorimeter] was eva luated as well as 17 ancillary symptoms before and after treatment; further more, pain intensity was followed up by means of a patient diary, until pai n recurrence. Results: Even with a single i.v. injection of 2 mg tropisetron a significan t pain reduction as well as an enhancement of the pain threshold provable b y dolorimetry could be achieved; however, this lasted only a few days. Thre e out of these 18 patients did not respond at all to therapy. If 2 mg tropi setron were applied daily for five days, 23 of 24 patients showed a pain re duction, which lasted for two weeks to two months in 20 of these patients. Two patients stopped filling in the pain diary. Twelve ancillary symptoms s uch as sleep disturbances, fatigue, morning stiffness, and others, were als o significantly improved by the latter treatment. In the global assessment 16 out of 24 patients showed a significant improvement and seven showed a s light improvement of their disease. There was only one patient who did not experience any improvement. Tolerability was good. Conclusion: Intravenous injection of 2 mg of the 5-HT3 receptor antagonist tropisetron once daily for five days can often produce a longer-lasting the rapeutic effect on fibromyalgia symptoms. The results achieved are now bein g evaluated in a randomized, placebo-controlled, double-blind trial.