An 87-year-old man with Alzheimer-type dementia presented to our hospital with pain in the right breast. A physical examination revealed nipple discharge and gynecomastia of the right breast (Picture 1, 2, arrows). He underwent treatment (1 mg risperidone) for 8 months for night delirium. His prolactin levels were increased [68.5 (normal: 3.6-12.8) ng/mL]; however, thyroid function test results were normal. Computed tomography revealed an enlarged right mammary gland. Pituitary magnetic resonance imaging showed no abnormality. Gynecomastia owing to risperidone-induced hyperprolactinemia was diagnosed. Therefore, risperidone, which was deemed the most likely to induce hyperprolactinemia (1), was discontinued. His breast pain and gynecomastia disappeared within few days (Picture 3, 4); however, his delirium worsened. Quetiapine 12.5 mg/day was initiated, which resolved his delirium; the patient's prolactin levels were 15.1 ng/mL at 6 months later. Dopamine (D2) receptor blockage by various drugs (especially antipsychotics, antidepressant, and prokinetics) causes increased prolactin secretion (1). Some atypical antipsychotics (clozapine, aripirazole, olanzapine, and quetiapine) do not increase prolactin secretion because of a low tendency to blockade dopamine receptors as well as a prolactin-sparing effect (1,2).
Picture 1.
Picture 2.
Picture 3.
Picture 4.
The authors state that they have no Conflict of Interest (COI).
References
- 1. Torre DL, Falorni A. Pharmacological causes of hyperprolactinemia. Ther Clin Risk Manag 3: 929-951, 2007. [PMC free article] [PubMed] [Google Scholar]
- 2. Peuskens J, Pani L, Detraux J, De Hert M. The effects of novel and newly approved antipsychotics on serum prolactin levels: a comprehensive review. CNS Drugs 28: 421-453, 2014. [DOI] [PMC free article] [PubMed] [Google Scholar]