EFFECTS OF IPSAPIRONE IN HEALTHY-SUBJECTS - A DOSE-RESPONSE STUDY

A dose-response study of ipsapirone (IFS), a 5HT(1a) partial agonist, was conducted in healthy male subjects. IPS was administered in doses of 5,10 and 20 mg PO in a placebo-controlled, double-blind design to 1 5 subjects on 4 test days separated by at least 3 days. Oral temperatu re, ACTH, cortisol, prolactin, blood pressure, pulse rate and behavior al variables were assessed every 30 min for 3 h after administration o f tablets (at 10:00 A.M.). IPS at 20 mg significantly decreased temper ature and increased cortisol levels. Although IPS increased ACTH level s at 20 mg, this effect was variable and not significant. IPS did not affect prolactin levels nor did it have any behavioral effects. Althou gh 20 mg IPS decreased blood pressure and pulse rate in one subject, o verall it had no significant effect on these parameters. IPS at 20 mg PO appears a useful probe to test 5HT(1a) function when temperature an d cortisol are used as response variables. These results replicate ear lier studies on the effect of IPS in healthy human subjects.