Background Clozapine is an atypical antipsychotic drug successfully used in the treatment of psychotic disorders. However, it is associated with life-threatening conditions including constipation and there is evidence to show that death from constipation may now exceed death from agranulocytosis.

Aim To discover the rate of constipation among clozapine-treated patients and to raise awareness of the need for thorough assessment and treatment of these patients.

Method At routine clinic appointments, 155 patients were asked about their bowel habit and use of laxatives using a nine-question structured interview form. Visual prompts were used including the Bristol stool chart and pictures of packaging from laxative products. Constipation was identified using the Rome III criteria.

Results Forty three per cent of the sample scored positively for constipation. Patients who took laxatives were between two and four times more likely to have constipation than those who did not take laxatives.

Conclusion All nursing staff need to be aware of the dangers associated with clozapine-induced constipation and that prescription of laxatives does not preclude patients being constipated.