Severe necrotic colitis in an adolescent with polypharmacy and high clozapine doses according to his ancestry.

The antipsychotic drug Clozapine (CLZ) is approved for treat-ment-resistant schizophrenia and reduction in the risk of recurrent suicidal behavior in schizophrenia or schizoaffective disorder. However, it is increasingly used in psychiatry and neurology worldwide in numerous off-label conditions. Clozapine is associated with diverse side effects which require careful monitor-ing in its use for prevention and treatment. The quality of CLZ use and pharma-covigilance varies considerably among Latin American countries. CLZ-induced gastrointestinal hypomotility (CIGH) is a relevant clinical problem, ranging from innocuous constipation to lethal necrotic colitis. Thus, optimal preven-tion, early detection, and treatment of CIGH deserves considerable attention. We describe here the case of a 15-year-old Mexican boy diagnosed with Opposi-tional Defiant- and Attention-Deficit/Hyperactivity Disorder who developed se-vere necrotic colitis after nine months of CLZ treatment, leading to permanent ileostomy. We ascribed this unfortunate outcome to careless polypharmacy that did not consider drug-related antimuscarinic activity, deficient clinical moni-toring, and lack of attention to ethnicity concerning drug dosing. This case is of educational value for the mental health team in order to promote the proper use of CLZ, which may be life-saving in patients with severe mental disorders.