New Drug Reviews

Timothy Grass Pollen Allergen Extract (Grastek) for Allergic Rhinitis


Am Fam Physician. 2015 Dec 15;92(12):1096-1097.

Timothy grass pollen allergen extract (Grastek) is a sublingual immunotherapy used to treat confirmed grass pollen–induced allergic rhinitis with or without conjunctivitis in patients five to 65 years of age.1

View/Print Table

DrugDosageDose formCost*

Timothy grass pollen allergen extract (Grastek)

One sublingual tablet daily

One tablet contains 2,800 bioequivalent allergy units


*—Estimated retail price of one month's treatment based on information obtained at (accessed October 13, 2015).

DrugDosageDose formCost*

Timothy grass pollen allergen extract (Grastek)

One sublingual tablet daily

One tablet contains 2,800 bioequivalent allergy units


*—Estimated retail price of one month's treatment based on information obtained at (accessed October 13, 2015).


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 near-fatal 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


The most common reactions are oral pruritus (26.7%), throat irritation (22.6%), ear pruritus (12.5%), and mouth edema (11.1%).1,3,4 About 5% of patients will discontinue treatment because of adverse effects.1,5 Patients typically continue treatment for an average of 0.6 years (vs. 1.7 years for subcutaneous immunotherapy), and only 7% of users will continue treatment for at least three years (vs. 23% of subcutaneous users).6 Patients of primary care physicians are more likely to continue treatment than those who see allergists or other subspecialists.6


Timothy grass pollen allergen extract has been compared with placebo in four clinical studies in North American patients

Address correspondence to Aaliyah Y. Rizvi, MD, at Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.


show all references

1. DailyMed. Drug label information: Grastek–phleum pratense pollen tablet. Accessed January 20, 2015....

2. Nelson HS. Oral/sublingual Phleum pretense grass tablet (Grazax/Grastek) to treat allergic rhinitis in the USA. Expert Rev Clin Immunol. 2014;10(11):1437–1451.

3. Blaiss M, Maloney J, Nolte H, Gawchik S, Yao R, Skoner DP. Efficacy and safety of timothy grass allergy immunotherapy tablets in North American children and adolescents [published correction appears in J Allergy Clin Immunol. 2011;128(2):436]. J Allergy Clin Immunol. 2011;127(1):64–71, 71.e1–4.

4. Nelson HS, Nolte H, Creticos P, Maloney J, Wu J, Bernstein DI. Efficacy and safety of timothy grass allergy immunotherapy tablet treatment in North American adults. J Allergy Clin Immunol. 2011;127(1):72–80, 80.e1–2.

5. Di Bona D, Plaia A, Leto-Barone MS, La Piana S, Di Lorenzo G. Efficacy of grass pollen allergen sublingual immunotherapy tablets for seasonal allergic rhino-conjunctivitis: a systematic review and meta-analysis. JAMA Intern Med. 2015;175(8):1301–1309.

6. Kiel MA, Röder E, Gerth van Wijk R, Al MJ, Hop WC, Ruttenvan Mölken MP. Real-life compliance and persistence among users of subcutaneous and sublingual allergen immunotherapy. J Allergy Clin Immunol. 2013;132(2):353–360.e2.

7. Maloney J, Bernstein Dl, Nelson H, et al. Efficacy and safety of grass sublingual immunotherapy tablet, MK-7243: a large randomized controlled trial. Ann Allergy Asthma Immunol. 2014;112(2):146–153.e2.

8. Murphy K, Gawchik S, Bernstein D, Andersen J, Pedersen MR. A phase 3 trial assessing the efficacy and safety of grass allergy immunotherapy tablet in subjects with grass pollen-induced allergic rhinitis with or without conjunctivitis, with or without asthma. J Negat Results Biomed. 2013;12:10.

STEPS new drug reviews cover Safety, Tolerability, Effectiveness, Price, and Simplicity. Each independent review is provided by authors who have no financial association with the drug manufacturer.

This series is coordinated by Allen F. Shaughnessy, PharmD, MMedEd, Contributing Editor.

A collection of STEPS published in AFP is available at


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