Timothy Grass Pollen Allergen Extract (Grastek) for Allergic Rhinitis.

The initial dose should be administered under the supervision of a physician because anaphylaxis and laryngopharyngeal edema have occurred in rare cases.1 The manufacturer suggests that timothy grass pollen allergen extract be avoided in patients taking beta blockers, alpha blockers, ergot alkaloids, tricyclic antidepressants, levothyroxine, monoamine oxidase inhibitors, chlorpheniramine, diphenhydramine (Benadryl), cardiac glycosides, or diuretics. These medications may interfere with epinephrine should it be needed to treat an anaphylactic reaction. Timothy grass pollen allergen extract is also contraindicated in patients with severe, unstable, or uncontrolled asthma; a history of allergic reaction to allergy immunotherapy; and eosinophilic esophagitis.1 There have been no reports of the fatal or nearfatal reactions that have occurred with use of subcutaneous immunotherapy.2 Timothy grass pollen allergen extract is U.S. Food and Drug Administration pregnancy category B. It is not known whether it is excreted in breast milk.1 TOLERABILITY