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Label Changes for:

Zyflo (zileuton) tablets and Zyflo CR (zileuton)  extended-release tablets

August 2009

Changes have been made to the PRECAUTIONS and ADVERSE REACTIONS sections of the safety label.

Detailed View: Safety Labeling Changes Approved By FDA Center for Drug Evaluation and Research (CDER) -- August 2009


Neuropsychiatric Events
  • Neuropsychiatric events have been reported in adult and adolescent patients taking zileuton, the active ingredient in Zyflo and zileuton extended-release tablets. Post-marketing reports with zileuton include sleep disorders and behavior changes. The clinical details of some post-marketing reports involving Zyflo appear consistent with a drug induced effect. Patients and prescribers should be alert for neuropsychiatric events. Patients should be instructed to notify their prescriber if these changes occur. Prescribers should carefully evaluate the risks and benefits of continuing treatment with Zyflo if such events occur.
Information for Patients
  • Patients should be instructed to notify their healthcare provider if neuropsychiatric events occur while using Zyflo.


Post-Marketing Experience
  • Cases of sleep disorders and behavior changes have also been reported