AimsWe aimed to assess and characterize sex differences in adverse drug reactions (ADRs) reported to the national pharmacovigilance centre in the Netherlands while considering differences in drug use. MethodsADRs spontaneously reported by healthcare professionals and patients to the Netherlands pharmacovigilance centre Lareb were used. Drug-ADR combinations reported at least 10 times between 2003-2016 for drugs used by 10,000 persons in that period were included. Data about the number of drug users was obtained from the National Health Care Institute. Sex-specific ADRs, like gynaecological problems, were excluded. Sex differences in specific drug-ADR combinations were tested using bivariate logistic regression analyses in which the number of drug users per sex was taken into account. ResultsIn total, 2483 drug-ADR combinations were analysed. Possibly relevant sex differences were shown in 363 combinations (15%). Most of these drug-ADR combinations were reported more often for women (322 combinations). Drugs with the highest number of ADRs that were more often reported for women included thyroid hormones (32 combinations) and antidepressants (16 combinations for the centrally acting sympathomimetics; 14 combinations for other antidepressants). Some ADRs were predominantly reported for women across a range of drugs such as headache and dizziness whereas other ADRs such as tendon ruptures and aggression were reported more often for men. ConclusionsIdentified sex differences in reported ADRs often referred to women. These differences may have various causes, including pharmacological and behavioural causes, which need to be further assessed. The results may ultimately lead to sex-specific prescribing or monitoring recommendations.