[Clinical relevance of drug interactions between sexual steroids and other medications]

Drug interactions of clinical relevance with hormonal contraceptives can occur with antibiotics, antiepileptic agents and anticoagulants. For a prevention, non hormonal contraceptives, short-term use of higher dosage of oral contraceptives or, for long-term application, continuous administration (i.e. without hormonal pause) of monophasic micro-pill preparations containing 30 micrograms ethinyl estradiol and higher progestin doses should be preferred. The contraceptive effect also can be impaired using barbiturates and rifampicin; the demand of insulin or oral antidiabetics can be altered during medication with oral contraceptives. Regarding investigations of possible drug interactions only few studies have been performed with hormonal replacement therapy in peri- and postmenopause. Drug interactions could develop above all treating risk patients with internal diseases. Treatment regimens using the physiological, human hormone estradiol instead of conjugated equine estrogens should be preferred. We recommend transdermal hormonal application especially if hepatic drug interactions could occur.