Concomitant Clozapine and Opium Usage Induced Constipation Leads to Fecal Impaction: A Case Report

Fecal impaction (FI) is a disorder characterized by the inability to evacuate large mass of compacted faces at any level of lower GI tract. The population with highest risk for FI includes elderly patients with neuropsychiatric disorders such as Alzheimer disease, schizophrenia, Parkinson disease, dementia, and severe stroke. Clozapine is an antipsychotic drug that can cause constipation and in some cases, progress to bowel obstruction and finally FI. Opium is a well-known etiology for constipation and its’ concomitant use with clozapine can have an additive effect on this complication. We present a 63-year-old man who had been treated for schizophrenia with clozapine (100 mg/TDS for 30 years) and who was using opium for about 20 years. This patient was presented with a history of constipation for 4 weeks, characterized by lack of urge to defecate as well as hard stool. We used a combination of normal saline and glycerin in our patient. In this case, successful therapy was focused on keeping the mechanical balance of colon, to clear out FI. We concluded that in patients who take opioids or with a history of psychotic disorders who had been treated with antipsychotic drugs, especially low-potency, first generation antipsychotics and clozapine presenting with abdominal pain and constipation should raise immediate concern.