Risperidone-Induced Priapism

BACKGROUND: Risperidone, a second-generation antipsychotic with strong alpha-1 adrenergic receptor affinity, has been associated with priapism, a rare but serious urological emergency. This adverse effect remains underrecognized in psychiatric settings. We synthesized published reports on risperidone-induced priapism, summarized clinical characteristics, and highlighted preventive and management strategies. METHODS: A systematic literature search was conducted across PubMed, EMBASE, Scopus, Medline, PubMed Central, Google Scholar, PsyArXiv, and PsycINFO from 1957 to 2024 using combinations of "risperidone," "risperdal," and "priapism." Eligible studies included those describing priapism following risperidone exposure. Non-human studies, reviews, editorials, and articles without full-text access were excluded. Reviewers independently screened articles and assessed their quality using the Joanna Briggs Institute appraisal tool; resolved discrepancies by a third investigator. RESULTS: From 987 screened records, 58 studies were included. Priapism occurred across all age groups and at a wide range of doses. Episodes were reported during both treatment initiation and maintenance. Risk factors included sickle cell disease, G6PD deficiency, cocaine or alcohol use, and prior prolonged erection. Management involved conservative measures, aspiration, intracavernosal sympathomimetics, and surgical shunting. Rechallenge frequently resulted in recurrence, whereas switching to agents with lower alpha-1 affinity, such as olanzapine or amisulpride, was typically effective. CONCLUSIONS: Risperidone-induced priapism can occur irrespective of dose or treatment duration, causing serious complications if unrecognized. This review highlights the importance of comprehensive evaluation before risperidone initiation, early identification, appropriate management, and clinician awareness of preventable adverse effects.