Domperidone-induced galactorrhea and abnormal uterine bleeding: a case report with review of clinical implications

Dopamine is a peripheral dopamine (D2) receptor antagonist that is widely prescribed for gastrointestinal symptoms and is often used as an over-the-counter drug. It can cause galactorrhoea through drug-induced hyperprolactinemia, an adverse effect that remains underrecognized in clinical practice. A 36-year-old multiparous woman was prescribed domperidone 10 mg twice daily for four weeks, together with pantoprazole, for gastro-oesophageal reflux disease. While responding well to treatment, she developed bilateral galactorrhoea on day 7 and abnormal uterine bleeding on day 21 of therapy. Serum prolactin was elevated (86.37 ng/ml), with reduced follicle-stimulating hormone (1.56 mIU/l), and pregnancy, thyroid dysfunction, and structural pelvic pathology were excluded. Domperidone-induced hyperprolactinaemia was diagnosed, and the drug was discontinued. Galactorrhoea resolved after 14 days and abnormal uterine bleeding after 23 days, with normalization of prolactin and follicle-stimulating hormone on repeat testing. Domperidone-induced hyperprolactinaemia should be considered in women presenting with galactorrhoea and menstrual disturbance, particularly abnormal uterine bleeding, which has not been well documented as a concurrent manifestation. Prompt recognition and drug discontinuation led to complete clinical and biochemical resolution, underscoring the need for thorough medication history-taking and patient counselling when prescribing domperidone.