Case Presentation:
A 56 year-old-female with past history of schizoaffective disorder on clozapine after failure of many antipsychotic medications for around 3 years got voluntarily hospitalized in a psychiatric facility for over 2 months and then presented to the acute care hospital with complains of fever, generalized fatigue and abdominal pain and admitted for SIRS without source. Abdominal CT scan done in the ED was unrevealing except for 1 mm right renal calculus and 1.2 cm hyperdensity consistent with ingested pills. Vitals were stable and abdominal exam was benign. She was on chlorpromazine and aripiprazole at presentation. Aripiprazole was discontinued. Bowel regimen was started with docusate and PEG. Fever subsided and hemodynamics improved but abdominal pain was persistent. She did not have bowel movement after multiple trials of bowel regimen including lactulose and enemas. GI consultation was done. Day 6: Colonoscopy was performed with limited examination to mid-sigmoid only due to hard stool and a repeat flexible sigmoidoscopy (day 7) failed similarly. Antipsychotic regimen was continued although suspected as cause of her constipation. Day 11: Fecal disimpaction was tried by surgical team with partial removal. She was started on a trial of Neostigmine. A day after (day 12) she decompensated and was taken to OR where perforation of sigmoid colon with peritonitis was found. Post-surgery she had a prolonged hospital stay for over a month.
Discussion: Clozapine is a common atypical antipsychotic commonly used in treatment-resistant schizophrenia. Constipation is a common side effect from its use. Up to 15 -60% patients using this medication experience significant distress from constipation. However the degree of constipation, if not proactively managed, can be very severe to the degree of causing significant organic complications including impaction, bowel obstruction, perforation and sometimes feculent emesis. Mortality as high as 27.5% have been reported if there is gastrointestinal hypomotility due to clozapine. The proposed mechanism is by virtue of anticholinergic and antiserotonergic action of this agent.
Conclusions: Constipation could be very debilitating side effect of clozapine and similar antipsychotic medications. Aggressive prophylactic management of bowel function is desirable. Even standing bowel regimen is justifiable to be used with this medication.