Assessing the sedative (adverse) effects of antiallergic drugs by quantitative electroencephalography: effects of setastine a non-sedating antihistaminic drug.

In order to assess the effects of Loderix (setastine) on the EEG ten healthy male volunteers were investigated in double-blind, placebo-controlled, cross-over arrangement. In addition to the test compound (Loderix) volunteers were treated with vehicle and with two referent drugs (terfenadine, Teldane, and chloropyramine HCl, Suprastin) possessing sedative effects of very different degrees. The different effects of the referent drugs on the central nervous system (CNS) were precisely indicated by the posterior alpha/theta ratio in the EEG. This marker parameter was affected by Loderix in the same direction as by Teldane and in the opposite direction as compared to Suprastin. In addition, Loderix increased the beta frequency range in the median areas of both hemispheres, moreover, it increased the total EEG power. The latter changes raise the question if Loderix has an "own" action on the EEG. (The observed "own" effect could not even be brought into connection with decrease of the vigilance level). The results strengthen the view that the action of Loderix on the EEG is similar to that of induced by Teldane, a drug very favourable in respect of the sedative side effects. Moreover, the drug did not affect the EEG power spectra in a direction that referred to sedative action. The spectral parameters in the "pharmaco" EEG recordings seem to be useful in the objective definition of the central (psychotropic) side-effects of drugs. This is a methodical achievement of the present study.