Brexpiprazole mitigates hyperprolactinaemia induced by paliperidone in a patient with a history of skin reaction to aripiprazole: case report introducing a new therapeutic approach.

Hyperprolactinaemia is a common adverse effect of antipsychotic medication, primarily resulting from dopamine D2 receptor blockade. It is characterised by menstrual irregularities, gynaecomastia, galactorrhoea and, with prolonged exposure, an increased risk of osteoporosis and breast cancer. When switching towards a prolactin-sparing antipsychotic is not feasible, adjunctive use of aripiprazole - a dopamine D2 partial agonist - has emerged as a validated strategy to mitigate hyperprolactinaemia without compromising antipsychotic efficacy. However, alternative options are needed for patients who cannot tolerate aripiprazole. Here we report the use of brexpiprazole, a dopamine D2 partial agonist structurally related to aripiprazole, to counteract paliperidone-induced hyperprolactinaemia effectively in a patient who developed a cutaneous reaction to aripiprazole. During the follow-up period with adjunctive brexpiprazole in combination with paliperidone, neither a recurrence of psychotic symptoms nor a reappearance of the skin reaction previously experienced with aripiprazole was observed.