The neuroendocrine effects of venlafaxine in healthy subjects

Venlafaxine hydrochloride represents a novel chemical class of antidepressant compounds. In preclinical studies it had monoamine uptake inhibitory properties. It specifically inhibited the uptake of serotonin (5‐HT) norepinephrine (NE) and dopamine (DA) in rat brain synaptosomes. Previous studies showed that various classes of psychotropic drugs with different effects on central aminergic systems exhibit distinct neuroendocrine profiles. In this study we investigated the effect of ascending doses of venlafaxine (12.5 mg, 25 mg, 50 mg, 75 mg orally) on neuroendocrine function in six healthy male subjects, using a single‐blind, placebo‐controlled study design. After the ascending doses of venlafaxine there could be demonstrated descriptively an influence on GH, and prolactin after the higher doses of venlafaxine. The cortisol secretion was statistically significantly influenced by venlafaxine, and showed a dose‐dependent increased. These neuroendocrine effects of venlafaxine may be interpreted as being a result of 5‐HT and NE reuptake‐inhibition properties of the substance. Evidence for a DA reuptake‐inhibition was not found as DA‐agonists lead to an inhibition of prolactin secretion.