Characterization of Admission Types in Medically Hospitalized Patients Prescribed Clozapine

Psychosomatics. Mar-Apr 2017;58(2):164-172. doi: 10.1016/j.psym.2016.11.013. Epub 2016 Nov 18.


Background: Clozapine is the antipsychotic of choice for treatment-resistant schizophrenia; however, rigorous monitoring is required to prevent or detect adverse drug events that contribute to morbidity and mortality. In addition to the Food and Drug Administration (FDA) boxed safety warnings specific to clozapine (agranulocytosis, hypotension, seizures, and cardiomyopathy/myocarditis), other adverse events such as pneumonia and gastrointestinal hypomotility have been reported in the literature to result in hospitalization.

Objective: To explore the reasons for medical hospitalization in patients prescribed clozapine, a retrospective chart review was completed.

Methods: Adults with schizophrenia or schizoaffective disorder prescribed clozapine were identified if they had a nonpsychiatric medical admission between 1/1/2003 and 8/1/2015. Demographics, admitting diagnosis, admitting service type, psychiatric consult information, clozapine dosing, and drug interactions were collected.

Results: Overall, 104 patients, representing 248 hospitalizations, were admitted to a medical unit during the study period. The predominant admission types were for the management of either pulmonary (32.2%) or gastrointestinal (19.8%) illnesses. The most common pulmonary diagnosis was pneumonia, accounting for 58% of pulmonary admissions. Further, 61.2% of the gastrointestinal admissions were related to hypomotility, ranging from constipation to death. Clozapine was discontinued owing to neutropenia in 2 patients; however, in both cases concomitant chemotherapy had been given.

Conclusion: In patients prescribed clozapine admitted to nonpsychiatric medical settings, gastrointestinal and pulmonary illnesses were common, but not illnesses related to boxed warnings. Additional research is needed to better assess the causality and true incidence of gastrointestinal or pulmonary events associated with clozapine. Furthermore, clinicians must be prepared to prevent, detect, and manage potentially life-threatening events associated with clozapine.

Keywords: clozapine; gastrointestinal hypomotility.; medical illness; pneumonia.

MeSH terms

  • Antipsychotic Agents / therapeutic use
  • Clozapine / therapeutic use*
  • Comorbidity
  • Female
  • Gastrointestinal Diseases / epidemiology*
  • Hospitalization / statistics & numerical data*
  • Humans
  • Lung Diseases / epidemiology*
  • Male
  • Middle Aged
  • Minnesota / epidemiology
  • Retrospective Studies
  • Schizophrenia / drug therapy*
  • Schizophrenia / epidemiology*


  • Antipsychotic Agents
  • Clozapine