Receptor occupancy theory-based analysis of interindividual differences in antiemetic effects of 5-HT3 receptor antagonists

Abstract

Background: The aim of this study was to estimate interindividual differences in the antiemetic effects of 5-HT(3) receptor antagonists by evaluating the influence of pharmacokinetics on 5-HT(3) receptor occupancies, based on receptor occupancy theory.

Methods: We analyzed interindividual differences of 5-HT(3) receptor occupancies and antiemetic effects after the oral and/or intravenous administration of standard doses of the following 5-HT(3) receptor antagonists: azasetron, granisetron, indisetron, ondansetron, ramosetron, and tropisetron.

Results: The interindividual difference between maximum and minimum 5-HT(3) receptor occupancies after oral administration ranged from 0.6% to 64.0%, and that difference after intravenous administration ranged from 0.6% to 29.6%. Following oral administration, the interindividual difference between maximum and minimum complete vomiting inhibition rates ranged from 0.2% to 16.1%. After intravenous administration, that difference ranged from 0.8% to 52.5%.

Conclusion: Interindividual differences in the clinical effects of 5-HT(3) receptor antagonists could be evaluated based on receptor occupancy theory, and the differences varied among drugs. Drug selection considering these individual variations might be useful for the patients who experienced vomiting associated with chemotherapy.