A mixed methods analysis of clozapine errors reported to the National Reporting and Learning System.

Issues with availability, stock, and supply were found to be the most common causes. This usually entailed a lack of stock to fulfil a patient's dose/supply. Such incidents could potentially be reduced by improved management of the supply process, and liaison between pharmacy and clinical staff. The implementation of emergency drug cupboards at the discretion of an on-call pharmacist may prove to be a preventative measure for such errors. Despite the potential adverse effects associated with clozapine, very few incidents led to moderate/severe harm. Encouragement of NRLS reporting is recommended for incidents of all degrees of harm.