Objective: Animal studies have shown that pindolol augmentation of selective serotonin re-uptake inhibitors (SSRIs) may act through inhibition of 5-HT(1A) autoreceptors in the raphe. The combination of pindolol plus a SSRI produces increased synaptic 5-HT levels that are greater than those achieved with a SSRI alone. However, it is unclear whether this actually occurs in humans, and clinical studies of pindolol augmentation have produced inconsistent results. Since the release of cortisol and prolactin is under serotonergic control, we hypothesized that pindolol augmentation of synaptic 5-HT concentrations produced by an SSRI in humans should lead to enhanced SSRI-induced cortisol and prolactin responses.
Methods: Cortisol and prolactin responses were measured after challenge tests with paroxetine (20-40 mg) plus pindolol (5 mg) and after paroxetine plus placebo in six non-depressed, healthy control subjects.
Results: No differences were observed in the cortisol or prolactin responses between either neuroendocrine challenge test.
Conclusions: These results suggest that SSRI augmentation with usual clinical doses of pindolol does not increase central synaptic 5-HT neurotransmission sufficient to induce an enhanced neuroendocrine response.