Sleep was then impaired during withdrawal, as indicated by decreased duration and poorer subjective quality, being worst on the 3rd withdrawal night.

On the basis of our open study findings ritanserin could be classified as a substance with antidepressive effects, with a low incidence of side-effects and a rapid onset of action.

Ritanserin was highly effective in reducing Pain Total Index and analgesic consumption in chronic headache, and its activity was similar to that observed during amitriptyline treatment. A significant improvement of HRSD and HRSA(Hamilton Rating Scale for Anxiety) scores was observed during both treatments.

IC50 values for histamine-H1, dopamine-D2, and adrenergic-alpha 1 and -alpha 2 sites were 39-, 77-, 107-, and 166-fold higher

The 5-HT2 antagonists reportedly produce a paradoxical down-regulation of 5-HT2 binding sites upon chronic treatment, rather than the expected supersensitivity. Chronic treatment with ritanserin (2.5 mg/kg/day for 7 days), but not mianserin (same regimen), attenuated a QMWS 24 h after the final injection, thus supporting with a functional measure, the down-regulation of such binding sites by ritanserin.

In contrast, ritanserin did not impair driving performance or affect objectively measured daytime sleepiness, while subjects reported to feel more alert during daytime.