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Lack of behavioural toxicity of mizolastine: a review of the clinical pharmacology studies


Dr P. Rosenzweig Clinical Pharmacology Department, Synthélabo Recherche, B.P. 110, 92225 Bagneux Cedex, France.


First-generation H1 antihistamines were associated with major sedative side-effects which were heavily disruptive to young active and aged patients when performing everyday activities. Mizolastine is a potent and selective H1-receptor antagonist which slowly penetrates into the brain and thus lacks the sedative effects of earlier antihistamines.

In this paper we present an overview of five clinical pharmacology studies which were carried out with a view to assessing mizolastine effects on psychomotor and skilled performances, and on cognitive functions in young and aged subjects.

The studies were all randomized, double-blind, placebo and (with the exception of one) active-drug controlled, cross-over studies. A total of 76 young and 15 aged subjects were enrolled. Two studies evaluated mizolastine over a range of doses (5–45 mg), and three involved a single or multiple administrations of the therapeutic dose (10 mg/day). Comparators were first generation (clemastine, tripolidine) and second generation (terfenadine, cetirizine) antihistamines. Drug effects were evaluated through standardized psychometric and memory tests, and subjective self-ratings (visual analogue scales). In two studies, driving performance was assessed using an actual driving test. Two studies investigated drug interaction with depressants of the central nervous system such as alcohol and lorazepam.

The results of the five reported studies were consistent in that mizolastine showed to be free from sedative effects when administered at the therapeutic dose. As with other newly developed antihistamines, some changes occurred at higher dose levels. At the therapeutic dose mizolastine did not alter driving performance and did not potentiate the depressant effects of alcohol and lorazepam.

Mizolastine was shown to be free from sedative effects that could affect the safe performance of everyday life activities in young and aged patients when administered at the therapeutic dose.