Aims: The aim of the present study was to estimate the relative risk of non-puerperal lactation in patients using antidepressants in general, and specifically for serotonergic (selective serotonin reuptake inhibitors (SSRIs) and clomipramine) and non-serotonergic antidepressants.
Methods: All suspected adverse drug reactions in women and reported from January 1986 until August 1996 to the Netherlands Pharmacovigilance Foundation, a spontaneous adverse drug reaction reporting programme, were analysed. Adverse drug reaction (ADR) reporting odds ratios, defined as the ratio of the exposure odds among reported cases of non-puerperal lactation to the exposure odds of reported other ADRs, were calculated adjusted for age and year of reporting.
Results: Thirty-eight cases of non-puerperal lactation were reported, of which 15 were associated with the use of antidepressant drugs. In general, antidepressants were associated with a higher risk of non-puerperal lactation in comparison with other drugs (ADR reporting odds ratio 8.3 [95%CI: 4.3-16.1]). Serotonergic antidepressants (selective serotonin reuptake inhibitors (SSRIs) and clomipramine) were associated with a higher risk (OR 12.7 [95%CI: 6.4-25.4]), whereas other antidepressants were not (OR 1.6 [95%CI: 0.2-11.6]), compared with all other drugs.
Conclusions: Our results indicate that serotonergic antidepressants are associated with an approximately eight times higher risk of non-puerperal lactation compared with other antidepressants. This effect is probably mediated by an indirect inhibition effect of serotonin on the dopaminergic transmission. This finding is in line with the occurrence of other antidopaminergic effects, such as extrapyramidal symptoms, in patients using serotonergic antidepressants.