Results of the intravenous administration of tropisetron in fibromyalgia patients.

The observed effects on the symptoms of fibromyalgia of daily oral administration of 5 mg of the 5-HT3 receptor antagonist, tropisetron, for 10 days, could be maintained or exceeded with intravenous administration of only 2 mg of the formulation. Following a single i.v. injection of 2 mg tropisetron, a more rapid and profound reduction in pain was achieved than with 5 mg oral tropisetron per day. In individual cases, patients who had previously experienced no reduction in pain from 10 days of 5 mg oral tropisetron daily responded to i.v. therapy. A more favourable and persistent effect on pain, combined with a simultaneous significant improvement in various vegetative and functional symptoms was achieved with five days treatment with 2 mg tropisetron i.v. per day. The results outlined and the possibility for rapid improvements with drug treatment of fibromyalgia should be confirmed in randomised, placebo controlled trials.