[Genotoxicity of oxazepam--the micronucleus cytochalasin-B test]

Oxazepam (OX) is one of the number benzodiazepines used therapeutically as a sedative-hypnotic and anti-anxiety agent. OX is also a common metabolite of many other benzodiazepines. Since they are among the most widely prescribed drug, the evaluation of their potential genotoxic activity should be considered very important. In the present study cytochalasin B-blocked binucleate human lymphocytes have been used to measure micronucleus induction after treatment with oxazepam. The frequency of micronuclei (MN) were analysed in 72 hours culture of peripheral blood human lymphocytes. OX was added to the cultures at the beginning of the cultivation period. The concentrations in cultures was 0.5; 5; 10; 25 and 50 mg/ml. It was found that all used oxazepam concentrations induced formation of micronuclei. MN frequencies were significantly increased (except for concentration 0.5 mg/ml OX) in relation to the control (cultures without OX). Number of binuclear lymphocytes with micronuclei, as well as number of micronuclei per a binuclear lymphocytes stand in correlation with the strength of tested concentrations--there was a dose-response. On the basis of our results we can conclude that long time administrated of OX may represent a potential hazard to human health.