GRASTEK is a prescription medicine used for sublingual (under the tongue) immunotherapy to treat Timothy and related grass pollen allergies that can cause sneezing, runny or itchy nose, stuffy or congested nose, or itchy and watery eyes. GRASTEK may be prescribed for persons 5 through 65 years of age who are allergic to grass pollen.

GRASTEK is taken for about 12 weeks before the grass pollen season and throughout the grass pollen season. GRASTEK may also be taken daily for 3 years to provide a sustained effect for a fourth year in which you do not have to take GRASTEK.

GRASTEK is NOT a medication that gives immediate relief for symptoms of grass allergy.

Important Safety Information about GRASTEK 

  • GRASTEK can cause severe allergic reactions that may be life-threatening. Stop taking GRASTEK and get medical treatment right away if you or your child has any of the following symptoms after taking GRASTEK:
    • Trouble breathing
    • Throat tightness or swelling
    • Trouble swallowing or speaking
    • Dizziness or fainting
    • Rapid or weak heartbeat
    • Severe stomach cramps or pain, vomiting, or diarrhea
    • Severe flushing or itching of the skin
  • Do not take GRASTEK if you or your child has severe, unstable or uncontrolled asthma; had a severe allergic reaction in the past that included trouble breathing, dizziness or fainting, or rapid or weak heartbeat; had difficulty with breathing due to swelling of the throat or upper airway after using any sublingual immunotherapy before; has ever been diagnosed with eosinophilic esophagitis; or is allergic to any of the inactive ingredients contained in GRASTEK.
  • For home administration of GRASTEK, your doctor will prescribe auto-injectable epinephrine, a medicine you can inject if you or your child has a severe allergic reaction after taking GRASTEK. Talk to your doctor or read the epinephrine patient information if you have any questions about the use of auto-injectable epinephrine.
  • The first dose of GRASTEK must be taken in the doctor’s office. After taking the first tablet, you or your child will be watched for at least 30 minutes for symptoms of a serious allergic reaction.
  • Children should be given each tablet of GRASTEK by an adult who will watch for any symptoms of a serious allergic reaction.
  • You should tell your doctor if you or your child is taking or has recently taken any other medicines, including medicines obtained without a prescription and herbal supplements. Keep a list of them and show it to your doctor and pharmacist each time you get a new supply of GRASTEK. Ask your doctor or pharmacist for advice before taking GRASTEK (Timothy Grass Pollen Allergen Extract).
  • Stop GRASTEK and contact your doctor if you or your child has any of the following after taking GRASTEK: Any type of a serious allergic reaction; throat tightness that worsens or swelling of the tongue or throat that causes trouble speaking, breathing or swallowing; asthma or any other breathing condition that gets worse or heartburn, difficulty swallowing, pain with swallowing, or chest pain that does not go away or worsens. Also stop taking GRASTEK following mouth surgery procedures (such as tooth removal) or if you or your child develop any mouth infections, ulcers or cuts in the mouth or throat.
  • The most commonly reported side effects were itching of the mouth, lips, or tongue, swelling under the tongue, or throat irritation. These side effects, by themselves, were not dangerous or life-threatening.
  • Your doctor may decide that GRASTEK is not the best treatment for you or your child if you or your child has asthma; plan to become pregnant or is breast-feeding; is unable or unwilling to administer epinephrine; or is taking certain medicines, including other allergen immunotherapy.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.