[Examination of hormonal contraceptives by enzyme induction (author's transl)].

The influence of drug stimulated biotransformation on the biological effectiveness of two different contraceptives (Deposition and Gravistat) was observed.--Phenobarbital, a potent enzyme inducer, is known to increase the metabolism of steroid hormones, including estrogens and progrestogens. -- The clinical symptoms of drug mediated enzyme induction of hormonal steroid contraceptives are dysfunctional bleedings. This phenomenon is discussed.