A 53-year-old male was admitted with non-resolving Priapism for 36 hours and was reviewed for advice regarding his psychotropic medications. He previously took Viagra about 2 days ago, and had an erection which resolved spontaneously. He underwent penile aspiration in the hospital which provided relief. Following that, he developed signs of infection which was treated with IV antibiotics. He was then waiting for further surgical correction.

He has a background history of psychotic illness and been treated with Quetiapine, Mirtazapine, Sertraline and Zopiclone, which were kept on hold during his admission. He reported that he currently suffers from depression and signs of psychosis, which take the form of auditory hallucinations and paranoid delusions.

He has been taking Viagra occasionally for years, but has not experienced side-effects like this before. He is a social drinker and previously smoked cannabis.

From the above scenario, there appears to be two clinical questions:

1. 1. Are the current medications responsible for his priapism?

2. 2. What medication(s) would be a suitable alternative if his priapism was indeed caused by his current drug regimen?

The major causes of Priapism are: direct trauma; haematological diseases; neurological diseases; cerebrovascular diseases; Medications; TPN and Neoplasm. Apart from medication side-effects, these other causes were ruled out.

The Summary of Product Characteristics for mirtazapine, sertraline, quetiapine and zopiclone were studied for their relative risk of causing priapism, and this is summarised below:

• • Mirtazapine: unknown

• • Sertraline: rare

• • Quetiapine: rare

• • Zopiclone: not listed

However, a paper by Salonia et al found that all the above medications except Zopiclone can increase the risk of priapism. Internationally published case reports also list priapism-associated medications as: risperidone; quetiapine; sildenafil; mirtazapine; citalopram; chlorpromazine and olanzapine.

Anti-psychotics cause priapism by Alpha-1 blockade and anticholinergic actions. Most of the antipsychotics have anticholinergic action. The medication which demonstrates the least alpha-1 blockade is Amisulpride which acts by blocking dopaminergic receptors in the brain.

Thus, it is clear from the above discussion that Amisulpride has the least possibility to cause Priapism. The patient was advised to take low dose Amisulpride and afterwards, no other complications were noted.