A 40-year old gentleman suffering from schizoaffective disorder since 2004, with co-morbid cocaine and cannabis abuse and parathyroidectomy was admitted to our psychiatric intensive care unit on 4th May 2018. Since admission he required eight episodes of seclusion due to extreme agitation. He failed to respond to several antipsychotics, however his mental state improved on the combination of zuclopenthixol decanoate 600mg/week, sodium valproate 2000mg/day and clonazepam 4-6mg/day. Because of the side effects of zuclopenthixol and past good response to clozapine; on 28th June 2018, he was commenced on clozapine, titrated to 300mg/day within 14 days. He made a marked progress after three weeks, however on 21st July, exactly 23 days, post clozapine he reported a prolonged, 12-hour painful erection. At the Accident and emergency (A&E) department, clozapine-induced priapism was confirmed; the patient received penile block and aspiration. clozapine was immediately stopped.
The patient refused to be re-challenged on clozapine and was instead commenced on risperidone (subsequently changed to paliperidone palmitate 150mg/monthly) alongside sodium valproate (2000mg/day). He made adequate progress, however, due to presence of negative symptoms and requiring further treatment on 20th August 2018 he was transferred to our local psychiatric rehabilitation unit. On 16th September 2018, he was taken to A&E again because of priapism that required drainage. This time, valproate-induced priapism was diagnosed; consequently, valproate was reduced from 2000mg/day to 1000mg/day. On 22nd September 2018, he had his 3rd priapism, which was again linked to sodium valproate, which was discontinued on 25th September. The patient continued paliperidone palmitate 150 mg/monthly and on 17th January 2019 discharged home. No further incidents of priapism have been reported since 22nd September 2018.
