Sex and gender differences in pharmacotherapy

Many drugs have act differently in women and men. Biological differences between women and men lead to sex differences in pharmacokinetics, i.e., in drug absorption, distribution in tissues, metabolism by liver enzymes, and excretion via the kidney and intestine. In addition there are sex differences in pharmacodynamics, leading to a different efficacy of drugs in women and men. The biological differences between women and men may be caused by sex-specific gene expression, by sex-specific epigenetic modifications, and finally by the effect of sex hormones. In addition, gender plays a role in drug efficacy as a sociocultural dimension that may lead to differences between women and men. Frequently drugs are only tested on animals of one sex and thereby optimized for one sex. This is based on the notion that sex differences are not important for clinical drug effects. Furthermore, to date, sex and gender differences have been underestimated in clinical studies, and phase III studies were not prospectively designed to assess sex differences in drug effects. In addition, women and men use drugs differently with respect to compliance, adherence, and self-medication with over-the-counter drugs. Further, it is known that male and female physicians treat women and men as patients differently. In conclusion, drug therapy is not yet optimized for both genders. However, there is increasing awareness that differences between women and men should be respected in order to provide optimal drugs in optimal doses for both genders.