Zileuton (trade name Zyflo) is an orally active inhibitor of 5-lipoxygenase, and thus inhibits leukotrienes (LTB4, LTC4, LTD4, and LTE4) formation, used for the maintenance treatment of asthma.

[1][2] Zileuton is indicated for the prophylaxis and chronic treatment of asthma in adults and children 12 years of age and older.

Research on mice suggests that Zileuton used alone or in combination with imatinib may inhibit chronic myeloid leukemia (CML).

Therefore, zileuton is contraindicated in patients with active liver disease or persistent hepatic function enzymes elevations greater than three times the upper limit of normal.

Zileuton is a weak inhibitor of CYP1A2[5] and thus has three clinically important drug interactions, which include increasing theophylline, and propranolol levels.

Elimination of zileuton is primarily through metabolites in the urine (~95%) with the feces accounting for the next largest amount (~2%).

[9] The most common adverse reactions reported by patients treated with Zyflo CR were sinusitis (6.5%), nausea (5%), and pharyngolaryngeal pain (5%) vs. placebo, 4%, 1.5%, and 4% respectively.

In addition, the herbal supplement St. John's wort may decrease the serum levels of zileuton.

If indicated, elimination of unabsorbed drug should be achieved by emesis or gastric lavage; usual precautions should be observed to maintain the airway.

A Certified Poison Control Center should be consulted for up-to-date information on management of overdose with Zyflo CR.