Comparison of the central and peripheral antihistamine effects of dimethindene maleate (Fenistil®) and its enantiomers

The H1 histamine receptor antagonist activity and sedative effects of dimethindene maleate racemate (DIM +/−) (FENISTIL®) and the individual enantiomers (DIM+ and DIM−) were monitored in parallel in a double-blind, placebo-controlled, cross-over study in 9 healthy subjects. Peripheral antihistamine activity (histamine-induced wheal and flare planimetry) and central effects (electroencephalography (EEG) and self-evaluation on a visual analogue scale (SEVS)) were measured after oral administration of a single dose of DIM+/− (4 mg), DIM+ (2 mg), DIM− (2 mg) and placebo.