Priapism following antipsychotic-gabapentinoid combination in a case of treatment-resistant schizophrenia: a case report.

BACKGROUND: Priapism is a prolonged penile erection that is described as a rare but serious event that constitutes a medical emergency. Drug-induced is commonly cited in the aetiology of priapism with several drug classes implicated in its onset (e.g. antipsychotics, antidepressants, anticonvulsants (gabapentinoids) and antihypertensives). The underlying mechanisms are thought to involve alterations in vascular tone and smooth muscle regulation, which may precipitate the onset of priapism.

CASE PRESENTATION: This report describes a 36-year-old male with schizophrenia and a history of chronic substance misuse including crack cocaine, heroin, methamphetamine and pregabalin, who developed ischaemic priapism during an acute psychotic episode on a psychiatric intensive care unit. At the time of the event, his regular medication regimen included a stable long-term dose of zuclopenthixol decanoate (500 mg weekly) and a recent initiation of low dose pregabalin (75 mg twice daily) for previously diagnosed neuropathic pain. The Naranjo adverse reaction probability scale score of eight suggested a probable association between the prescribed psychotropics and ischaemic priapism.

CONCLUSIONS: Priapism requires urgent recognition and management to prevent long-term complications. In psychiatric settings, clinicians should exercise caution when combining gabapentinoids alongside antipsychotics, as this may increase the risk of priapism. This case highlights the need for careful monitoring when prescribing gabapentinoids to patients on long-term antipsychotics, particularly in psychiatric inpatient settings where delayed recognition may increase morbidity.

CLINICAL TRIAL NUMBER: Not applicable.