Do cytochrome enzymes influence the therapeutic effect of tropisetron in fibromyalgia?

Abstract

It is well known that the 5-HT3 receptor tropisetron shows a bell-shaped dose-response curve in the treatment of pain associated with fibromyalgia. The best results are achieved with a daily oral dose of 5 mg for 10 days. Dosages of 10 and 15 mg per day have a much weaker effect. If tropisetron is administered by intravenous injection, a regimen of 5 mg per day over 5 days will suffice to reduce pain substantially. An open study of selected cases revealed that 2 mg of tropisetron daily for 5 days also yielded satisfactory pain reduction, whereas this was not observed in a placebo-controlled double-blind study. We therefore investigated which factors might be responsible for the different effects of the drug. Judging from the above-mentioned studies, the effect of a minimum dosage of tropisetron could be assumed to be partly attributable to the different half-life periods. This is supported by the markedly different rates of constipation, a characteristic side effect of the drug, reported by the two studies.

• Authors: T Stratz, F Kees, W Müller
• Journal: Drugs under experimental and clinical research (Drugs Exp Clin Res) Vol. 29 Issue 2 Pg. 91-4 ( 2003) ISSN: 0378-6501 [Print] Switzerland
• PMID: 12951840 (Publication Type: Clinical Trial, Journal Article)

Chemical References

• Indoles
• Serotonin Antagonists
• Tropisetron
• Cytochrome P-450 Enzyme System

Topics

• Adult
• Cytochrome P-450 Enzyme System (metabolism)
• Female
• Fibromyalgia (drug therapy)
• Half-Life
• Humans
• Indoles (blood, metabolism, therapeutic use)
• Injections, Intravenous
• Middle Aged
• Pilot Projects
• Serotonin Antagonists (blood, metabolism, therapeutic use)
• Treatment Outcome
• Tropisetron