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Grass Pollen Allergen Extract (Timothy Grass)

Pronunciation

(GRAS POL uhn al er juhn EK strakt TIM oh thee GRAS)

Index Terms

  • Timothy Grass

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet Sublingual, Sublingual:

Grastek: 2800 bau [contains gelatin (fish)]

Brand Names: U.S.

  • Grastek

Pharmacologic Category

  • Allergen-Specific Immunotherapy

Pharmacology

Grass pollen allergen extract contains extract from timothy grass. While the exact mechanism has not been fully elucidated, specific immunotherapy (SIT) may act by inducing a switch from T helper 2 cell response (Th2) to T helper 1 cell (Th1) response resulting in decreased interleukin-4 (IL-4) and interleukin-5 (IL-5) and increased interleukin-10 (IL-10), production of IgG-blocking antibodies that compete with IgE antibodies for allergen binding, proliferation of regulatory T lymphocytes and cytokines, and decreases in mast cells, eosinophils, and early- and late-phase allergic responses (Leith 2006).

Use: Labeled Indications

Grass pollen-induced allergic rhinitis: Immunotherapy for the treatment of grass pollen-induced allergic rhinitis with or without conjunctivitis confirmed by positive skin test or in vitro testing for pollen-specific IgE antibodies for timothy grass or cross-reactive grass pollens in patients 5 through 65 years of age. Not indicated for the immediate relief of allergy symptoms.

Contraindications

Hypersensitivity to any of the inactive ingredients (gelatin, mannitol, and sodium hydroxide) contained in this product or any other component of the formulation; severe, unstable or uncontrolled asthma; history of any severe systemic allergic reaction; history of any severe local reaction to sublingual allergen immunotherapy; history of eosinophilic esophagitis

Canadian labeling: Additional contraindications (not in US labeling): Unstable, severe chronic, or severe seasonal asthma (FEV1 <70% of predicted value in adults; <80% in children); concomitant beta-blocker therapy; oral inflammation (eg, oral lichen planus, oral ulcerations, severe oral candidiasis, or dental extraction)

Dosing: Adult

Dosage strength expressed in Bioequivalent Allergy Units (BAU). Note: Initiate treatment ≥12 weeks before expected onset of each pollen season and continue throughout pollen season. May be taken daily for 3 consecutive years (including intervals between grass pollen seasons). Safety and efficacy of initiating treatment during grass pollen season or restarting treatment after missing a dose have not been established. In clinical trials, treatment interruptions ≤7 days were allowed.

Grass pollen-induced allergic rhinitis: Adults ≤65 years: Sublingual: One tablet (2,800 BAU) once daily

Dosing: Pediatric

Note: Dosage strength expressed in Bioequivalent Allergy Units (BAU). Initiate treatment ≥12 weeks before expected onset of each grass pollen season and continue throughout pollen season. May be taken daily for 3 consecutive years (including intervals between grass pollen seasons). Safety and efficacy of initiating treatment during grass pollen season or restarting treatment after missing a dose have not been established. In clinical trials, treatment interruptions ≤7 days were allowed.

Grass pollen-induced allergic rhinitis: Children ≥5 years and Adolescents: Sublingual: 1 tablet (2,800 BAU) once daily. First dose should be administered in a health care setting due to the potential for allergic reactions.

Administration

Sublingual: Administer first dose in a healthcare setting due to the potential for allergic reactions; monitor patient for 30 minutes after first dose. If well tolerated, subsequent doses may be taken at home. Remove sublingual tablet from blister unit with dry hands immediately prior to administration. Place tablet under tongue until completely dissolved (≥1 minute) and then swallow. Wash hands after handling tablet. Avoid food or beverage for 5 minutes following dissolution of tablet (to prevent the swallowing of allergen extract). Auto-injectable epinephrine should be made available to patients.

Storage

Store between 20°C and 25°C (68°F and 77°F); excursions are permitted between 15°C and 30°C (59°F and 86°F). Protect from moisture.

Drug Interactions

There are no known significant interactions.

Adverse Reactions

>10%:

Dermatologic: Pruritus of ear (7% to 13%)

Gastrointestinal: Oral itching (24% to 27%)

Hypersensitivity: Mouth edema (10% to 11%)

Respiratory: Throat irritation (21% to 23%)

1% to 10%:

Cardiovascular: Chest discomfort (2%), lip edema (adults: 1%)

Central nervous system: Headache (2% to 3%), oral hypoesthesia (1% to 2%), fatigue (adults: 1%)

Dermatologic: Tongue pruritus (6% to 9%), lip pruritus (children and adolescents: 3%), pruritus (adults: 2%), urticaria (2%)

Endocrine & metabolic: Palatal edema (adults: 1%)

Gastrointestinal: Oral paresthesia (5% to 10%), lip swelling (4% to 7%), oral mucosa erythema (2% to 5%), swollen tongue (3%), dyspepsia (adults: 2%), nausea (2%), oral discomfort (2%), dysphagia (1% to 2%), glossalgia (1%), glossitis (adults: 1%), stomatitis (1%), tongue disease (adults: 1%), abdominal pain (adults: ≤1%), gastroesophageal reflux disease (adults: ≤1%)

Ophthalmic: Eye pruritus (children and adolescents: 3%)

Respiratory: Pharyngeal erythema (children and adolescents: 4%), oropharyngeal pain (2% to 4%), cough (children and adolescents: 3%), pharyngeal edema (3%), dry throat (adults: 2%), nasal congestion (children and adolescents: 2%), nasal discomfort (2%), sneezing (children and adolescents: 2%), dyspnea (1% to 2%), constriction of the pharynx (adults: 1%)

Postmarketing and/or case reports: Anaphylactic shock, anaphylaxis, angioedema, cardiac rate disturbance, chest pressure, decrease in forced vital capacity, diarrhea, dizziness, drowsiness, dysarthria, eosinophilic esophagitis, exacerbation of asthma, exacerbation of ulcerative colitis, exercise-induced asthma, facial edema, facial erythema, foreign body sensation, hoarseness, hypersensitivity reaction, hyperventilation, hypotension, impaired consciousness, increased heart rate, laryngeal discomfort, laryngitis, local hypersensitivity reaction, neck edema, oral mucosa ulcer, oxygen saturation decreased, peak expiratory flow rate decreased, localized swelling (enlarged uvula), pneumonia, reduced forced expiratory volume, respiratory distress, skin rash, status asthmaticus, stridor, tremor, vomiting, wheezing

ALERT: U.S. Boxed Warning

Severe allergic reactions:

Grass pollen allergen extract can cause life-threatening allergic reactions such as anaphylaxis and severe laryngopharyngeal restriction. Do not administer to patients with severe, unstable, or uncontrolled asthma. Observe patients in the office for at least 30 minutes following the initial dose. Prescribe auto-injectable epinephrine, instruct and train patients on its appropriate use, and instruct patients to seek immediate medical care upon its use. Grass pollen allergen extract may not be suitable for patients with certain underlying medical conditions that may reduce their ability to survive a serious allergic reaction. Grass pollen allergen extract may not be suitable for patients who may be unresponsive to epinephrine or inhaled bronchodilators, such as those taking beta-blockers.

Warnings/Precautions

Concerns related to adverse effects:

• Esophagitis: Eosinophilic esophagitis has been reported with sublingual tablet immunotherapy; discontinue therapy in patients who experience severe or persistent gastroesophageal symptoms (eg, dysphagia, chest pain). Use is contraindicated in patients with a history of eosinophilic esophagitis.

• Hypersensitivity reactions [US Boxed Warning]: Severe, life-threatening allergic reactions, including anaphylaxis and severe laryngopharyngeal restrictions, may occur. Local reactions in the mouth or throat may occur; consider discontinuation in patients experiencing escalating and persistent adverse reactions in the mouth or throat. Increased risk of local or systemic adverse reactions may occur when given with concomitant allergen immunotherapy.

Disease-related concerns:

• Respiratory disease: [US Boxed Warning]: Do not administer to patients with severe, unstable, or uncontrolled asthma; use has not been studied in patients with moderate or severe asthma or in patients requiring daily medication. Withhold treatment if patient is experiencing an acute asthma exacerbation. Re-evaluate patients with recurrent asthma exacerbations and consider discontinuation.

Concurrent drug therapy issues:

• Vaccines: Effect of vaccination during therapy has not been evaluated.

Other warnings/precautions:

• Administration: [US Boxed Warning]: Auto-injectable epinephrine should be prescribed to patients; instruct patients on appropriate use and to obtain immediate medical care upon its use.

• Appropriate patient selection: [US Boxed Warning]: Use may not be suitable for patients with conditions that may reduce their ability to survive a serious allergic reaction, including but not limited to compromised lung function (either chronic or acute) and cardiovascular conditions (eg, unstable angina, recent MI, arrhythmia, and uncontrolled hypertension).

• Appropriate use: [US Boxed Warning]: Use may not be suitable for patients who may be unresponsive to epinephrine or inhaled bronchodilators due to concomitant drug therapy. The effect of epinephrine may be potentiated or inhibited by the following medications: beta blockers, alpha blockers, ergot alkaloids, tricyclic antidepressants, levothyroxine, monoamine oxidase inhibitors, antihistamines, cardiac glycosides, and diuretics.

• Monitoring: [US Boxed Warning]: Monitor all patients for at least 30 minutes after initial dose in a health care setting under the supervision of a physician with experience in the diagnosis and treatment of allergic diseases. Each subsequent dose in pediatric patients should be done under direct adult supervision.

• Oral inflammation/wounds: Discontinue therapy to allow for complete healing of the oral cavity due to oral inflammation (eg, oral lichen planus, mouth ulcers, or thrush) or oral wounds following oral surgery or dental extraction.

Monitoring Parameters

Signs/symptoms of hypersensitivity; monitor patients for at least 30 minutes after administration of first dose.

Pregnancy Considerations

In general, allergen immunotherapy is not initiated during pregnancy. Sublingual therapy should be held in newly pregnant patients (Cox 2011; Epstein 2017).

Patient Education

What is this drug used for?

• It is used to treat allergies caused by Timothy grass pollen.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Itching in the ear, mouth, or tongue

• Numbness or tingling of the mouth

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Trouble swallowing

• Painful swallowing

• Trouble speaking

• Heartburn

• Chest pain

• Fast heartbeat

• Passing out

• Dizziness

• Flushing

• Shortness of breath

• High-pitched abnormal breathing sound

• Persistent cough

• Severe diarrhea

• Severe nausea

• Vomiting

• Abdominal cramps

• Severe abdominal pain

• Severe mouth irritation

• Thrush

• Severe sore throat

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine's uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.