Effect of oral ondansetron on total cholecystokinin plasma levels following CCK-4 panic challenge procedure in healthy men

To gain insight into whether ondansetron treatment induces changes in total cholecystokinin (CCKT) plasma levels before and after administration of the cholecystokinin tetrapeptide (CCK-4) panic challenge procedure in healthy men. Thirty-eight volunteers received a 50-microgram bolus of CCK-4 60 minutes after a single oral dose (acute treatment) and multiple oral doses (chronic treatment) of ondansetron or placebo. Results showed no difference in CCKT plasma levels of CCKT elimination rate constant between the ondansetron and the placebo groups after either acute or chronic treatment. Results from this study suggest that total CCK plasma levels are not influenced by either acute or chronic treatment with ondansetron. However, the effect of ondansetron on the different CCK component fractions still needs exploration.