New Zealand - The Medicines and Medical Devices Safety Authority (Medsafe) recommends reducing the dosage, or changing to an atypical antipsychotic agent, when patients receiving typical antipsychotics or risperidone (an atypical antipsychotic with high affinity for dopamine-2 receptors) experience symptomatic hyperprolactinaemia.

Hyperprolactinaemia occurs when dopamine-2 receptors are blocked by typical antipsychotics and risperidone, causing hypogonadism. In premenopausal women, low estrogen levels resulting from high prolactin levels could contribute to decreasing bone mineral density. A menstrual history should be acquired to monitor for hyperprolactinaemia before such women commence treatment with antipsychotics. Hyperprolactinaemia has also been linked to an increased risk of breast cancer in animal and in vitro studies.

Medsafe recommends that following the exclusion of other causes of hyperprolactinaemia, patients should be switched to a prolactin-sparing antipsychotic, or the dosage of their existing medication should be reduced if their mental status is stable. Such regimen changes should be accompanied by close psychiatric monitoring, and should not be considered for patients with asymptomatic hyperprolactinaemia. An endocrinologist should be consulted and hormone replacement considered in cases where implementing the recommended regimen changes proves difficult.

Reference: Medsafe Media Release, May 2001. Available on http://www.medsafe.govt.nz