Effect of tropisetron on circulating catecholamines and other putative biochemical markers in serum of patients with fibromyalgia

Objective: The aim of the study was to assess the influence of the 5HT(3)-r eceptor antagonist tropisetron on circulating catecholamines as biochemical markers of the activity of the sympathoadrenal system in fibromyalgia. Mor eover, serum concentrations of serotonin, somatomedin C, oxytocin, calciton in-gene-related-peptide, calcitonin and cholecystokinin were assayed as put ative markers in pain-related disorders like primary fibromyalgia. Methods: In 96 patients, who met the ACR classification criteria for fibrom yalgia, and in 20 sex and age matched controls concentrations of dopamine, noradrenaline, adrenaline, serotonin and tropisetron were assayed in serum by HPLC with electrochemical detection. All other transmitters were determi ned by ELISA. Results: There was with the exception of tropisetron, calcitonin and dopami ne, no correlation between doses of tropisetron 5, 10, 15 mg respectively a nd significant changes in circulating transmitters or other transmitters as putative biochemicals markers in primary fibromyalgia. Regarding the predi ction of pain reduction to tropisetron, patients with elevated dopamine and /or reduced plasma 5-HT concentrations tended to show a higher response rat e. Conclusion: Despite these partly disappointing results another prospective pilot study with selected patients vs. age and sex matched controls, double blind and with comparison of other 5HT(3)-receptor antagonists e.g. dolase tron and granisetron e.g. after i.v. bolus injection is suggested. Still th e data obtained in this preliminary paper provide some evidence regarding t he present discussion on subgroups of patients with primary fibromyalgia.