Important Safety Information

ZYFLO CR^® is a leukotriene synthesis inhibitor indicated for the prophylaxis and chronic treatment of asthma in adults and children 12 years of age and older. Do not use ZYFLO CR^® to treat an acute asthma attack.

ZYFLO CR^® is contraindicated for patients with active liver disease or persistent hepatic function enzyme elevations  3 times the upper limit of normal. Assessment of hepatic function enzymes prior to and during ZYFLO CR^® therapy should be undertaken. ZYFLO CR^® is also contraindicated for patients with a history of allergic reactions to zileuton or any of the other ingredients.

The active ingredient in ZYFLO CR^® increases theophylline, warfarin, and propranolol levels. Dose adjustment of these other drugs and patient monitoring may be required. ZYFLO CR^® should be used with caution in patients who consume substantial quantities of alcohol and/or have a history of liver disease. Neuropsychiatric events, including sleeping disorders and behavioral changes, may occur with ZYFLO CR^®.

The most common adverse reactions (5%) include: sinusitis, nausea, and pharyngolaryngeal pain.