A 49-year-old male, known to have been suffering from paranoid schizophrenia for 10 years, was treated twice with clozapine. Although the clozapine alleviated his psychosis, the patient developed peri-orbital oedema repeatedly. As a result he requested a switch to a different antipsychotic. Also, while the patient was on clozapine, it proved difficult to regulate his hypertension. A possible explanation for these two side-effects is that clozapine blocks the renal dopamine D4 receptor, preventing it from performing its normal natriuretic and diuretic function. In view of the high
but largely unnoticed incidence of hypertension in patients on clozapine (4%), we advise that such patients should receive structured somatic screening in a clinical setting.