Effects of subchronic paroxetine administration on night-time endocrinological profiles in healthy male volunteers

To evaluate the subchronic effects of paroxetine, a selective serotonin reu ptake inhibitor, on nocturnal endocrinological profiles, eight healthy male volunteers with no personal or family history of a psychiatric or neurolog ical disease were administered paroxetine (30 mg/day) or placebo in a doubl e-blind cross-over design. Drugs were given as a single dose at 10:00 h for a period of 4 weeks each. Between days 21 and 28 of each treatment period, sleep EEG was registered for four consecutive nights from 23:00 to 07:00 h . During the last night, hormonal profiles for prolactin, growth hormone (G H), cortisol, corticotropin (ACTH), luteinizing hormone (LH), testosterone and melatonin were determined, and area-under-the-curve values were calcula ted. None of the endocrinological parameters revealed any statistically sig nificant changes. A trend could be found for an increased cortisol producti on under paroxetine (P = 0.069). ACTH, LH, and melatonin showed slight and non-significant decreases. Prolactin release was only marginally elevated ( + 7%). The mean sleep onset GH release (as measured for a time period of 1 80 min after sleep onset) was decreased by about 30% under paroxetine. Howe ver. statistical significance could not be reached. For hGH, there was a de layed mean GH-peak under paroxetine. Nocturnal testosterone secretion remai ned almost unaltered. The lack of significant endocrinological alterations might be partially explained by both adaptational phenomena under subchroni c treatment conditions and the extended time span between the single mornin g dose and the registration period, respectively. (C) 2000 Elsevier Science Ltd. All rights reserved.