One of the many medications used for treating asthma is zileuton (Zyflo®), a prescription drug used specifically to prevent asthma attacks. It is taken daily and is not meant to be taken as a treatment for an attack that has already started.
Most people tolerate it well. However, as with any medication, side effects are possible. In clinical studies, common reactions included:
(Click Zileuton for more information on this drug. This article covers how it works, generic availability, and why you can now only purchase the long-acting version of the drug.)