FDA Strengthens Clozapine Constipation Warning

FDA has strengthened an existing warning of constipation associated with the use of clozapine, stating that this constipation can, uncommonly, progress to serious bowel complications, including blockage of the bowel.

These issues can lead to hospitalization and death if not dealt with quickly.

  • FDA recommends that health care professionals:
  • Evaluate bowel function in patients prior to clozapine initiation.
  • Avoid co-prescription of clozapine and other anticholinergic medications.
  • Advise patients of the risk of constipation and the need to stay hydrated.
  • Question patients about their bowel function throughout treatment.
  • Advise patients to alert health care providers if they experience difficulty with bowel movements or passing gas.
  • Monitor patients for symptoms of gastrointestinal hypomotility, including nausea, abdominal distension or pain, and vomiting.
  • Consider the use of prophylactic laxative treatment when initiating clozapine in patients with a history of constipation or bowel obstruction.

“Healthcare professionals and patients are encouraged to report adverse events or side effects related to the use of these products to the FDA's MedWatch Safety Information and Adverse Event Reporting Program,” FDA wrote.

—Michael Potts

Clozaril, Fazaclo ODT, Versacloz (clozapine): drug safety communication - FDA strengthens warning that untreated constipation can lead to serious bowel problems [press release]. Silver Spring, MD: Food and Drug Administration; January 28, 2020. Accessed January 29, 2020