Abstract
Atypical antipsychotics, including lurasidone, are increasingly prescribed due to their perceived lower risk of side effects. We present the case of a 65‐year‐old woman with longstanding BPAD who developed symptoms of urinary retention (UR), confirmed on bladder ultrasound, soon after beginning lurasidone monotherapy for bipolar affective disorder (BPAD) management. Despite dose reduction and addition of tamsulosin, symptoms of UR persisted and only resolved with cessation of lurasidone. The causal relationship between lurasidone and UR was assessed using the Naranjo Adverse Drug Reaction (ADR) Probability Scale, yielding a score of 8, indicating a highly ‘probable’ ADR. A literature review revealed only two prior reports of lurasidone‐associated UR, highlighting the rarity of this presentation. This case underscores the need for clinicians to remain vigilant for UR in patients prescribed lurasidone, or other atypical antipsychotics, despite their generally favourable side effect profile. Early recognition and management are critical to prevent complications and ensure appropriate ongoing treatment of BPAD.