skip to main content

Antipsychotic-induced hyperprolactinaemia — MRCPsych Paper A MCQ

Instant feedback + full explanation. One question, done properly.

EasyPsychopharmacologyAntipsychotic-induced hyperprolactinaemiaMRCPsych Paper A

A 26-year-old woman develops galactorrhoea and amenorrhoea after starting risperidone. Pregnancy testing is negative and her serum prolactin concentration is raised. Which pharmacological action of risperidone most directly explains this presentation?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Blockade of dopamine D2 receptors in the tuberoinfundibular pathway

The correct answer is E. Dopamine released by tuberoinfundibular neurons normally activates D2 receptors on anterior pituitary lactotrophs, providing tonic inhibition of prolactin secretion. Risperidone antagonises D2 receptors, removing this inhibition and increasing prolactin. Hyperprolactinaemia can suppress gonadotropin secretion and cause amenorrhoea, galactorrhoea, sexual dysfunction and impaired fertility. Histamine H1 receptor blockade is principally associated with sedation and increased appetite or weight gain. Serotonin 5-HT1A activity does not account for risperidone-associated prolactin elevation. AMPA receptor blockade and beta-2 adrenoceptor agonism are not relevant mechanisms of risperidone-induced hyperprolactinaemia.

Reference: Electronic Medicines Compendium, Risperidone 1 mg/ml oral solution: Summary of Product Characteristics, sections 4.4 and 5.3, updated 14 July 2026. https://www.medicines.org.uk/emc/product/4364/smpc