Fluoxetine brakes the menstrual cycle: Uncovering the unexpected effect

Fluoxetine is one of the most commonly used antidepressants, classified under selective serotonin reuptake inhibitors (SSRIs). It is indicated for the treatment of depression, obsessive-compulsive disorder, anxiety, and eating disorders. The antidepressant effect of fluoxetine is achieved by inhibiting the reuptake of serotonin (5-HT) via the serotonin transporter (SERT) in neurons. Although fluoxetine is generally considered safe and well-tolerated by most patients, this case series describes instances where patients treated with fluoxetine subsequently developed menstrual irregularities. Upon discontinuation of fluoxetine, the menstrual cycles returned to normal. To the best of our knowledge, there is a lack of precise data associating fluoxetine with the onset of menstrual irregularities. This effect may be related to its central serotonergic action via 5-HT action modulates the prolactin, estradiol, and progesterone level. Therefore, physicians should be aware of the potential risk of fluoxetine-induced menstrual irregularities.