timothy grass pollen allergen extract

General

Pronunciation:
ti-moe-thee grass po-len al-ler-gen ex-trakt

Trade Name(s)

• Grastek

Ther. Class.
allergy, cold and cough remedies

Pharm. Class.
immunotherapy

Indications

Treatment of timothy grass-induced allergic rhinitis with/without conjunctivitis, confirmed by testing to be associated with the presence of pollen-specific IgE antibodies.

Action

Small doses of antigen produce T-cell activation and downregulation of mucosal mast cells; additional effects include ↓ IgE production, ↑ specific immunoglobulin G4 (IgG4) production and changes in interleukin and eosinophil activity.

Therapeutic Effect(s):

Decreased symptoms (rhinitis/conjunctivitis) and need for daily medication to control symptoms.

Pharmacokinetics

Absorption: Allergen is absorbed and processed from oral mucosa and GI tract.

Distribution: Unknown.

Metabolism and Excretion: Unknown.

Half-life: Unknown.

TIME/ACTION PROFILE (decrease in symptoms/need for medications)

Contraindication/Precautions

Contraindicated in:

• Severe/unstable/uncontrolled asthma
• History of severe allergic or other reaction to sublingual immunotherapy
• History of eosinophilic esophagitis
• History of hypersensitivity to inactive ingredients.

Use Cautiously in:

• Oral inflammation/wounds including oral surgery/dental extraction, oral lichan planus, mouth ulcers or thrush (discontinue temporarily)
• Patients who may not respond to epinephrine/bronchodilators including those taking beta-blockers
• OB: Use during pregnancy only if clearly needed (systemic/local adverse reactions may be poorly tolerated during pregnancy);
• Lactation:Use cautiously if breastfeeding;
• Pedi: Safe and effective use in children <5 yr has not been estblished.

Exercise Extreme Caution in:

Any medical condition that may preclude surviving a serious allergic reaction.

Adverse Reactions/Side Effects

CNS: fatigue, headache

EENT: ear pruritus, throat irritation, dry throat, eye pruritus, nasal discomfort, oropharyngeal pain, pharyngeal edema, sneezing, throat tightness

Resp: dyspnea

CV: chest discomfort

GI: mouth edema, oral pruritus, dyspepsia, dysphagia, glossitis, glossodynia, lip swelling, oral hypoesthesia, oral mucosal erythema, oral paraesthesia, stomatitis, swollen tongue, palatal edema, tongue pruritus

Derm: pruritus, urticaria

Misc: ALLERGIC REACTIONS INCLUDING ANAPHYLAXIS/LARYNGOPHARYNGEAL RESTRICTION

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

• Concurrent allergen immunotherapy may ↑ risk of adverse reactions.
• Concurrent beta blockers may ↓ response to bronchodilators or parenteral epinephrine if required for severe allergic reactions to pollen extract.
• Alpha blockers and beta blockers blunt the beneficial effects of epinephrine which may be required to treat anaphylaxis (↑ dose of epinephrine may be required).
• Ergot alkaloids may reverse the pressor effects of epinephrine.
• Effects of epinephrine may be ↑ by tricyclic antidepressants , levothyroxine , MAO inhibitors and some antihistamines including chlorpheniramine and diphenhyramine .
• Cardiac glycosides may ↑ risk of adverse cardiovascular events with epineprine.

Route/Dosage

SL: (Adults and Children 5–65 yr): One tablet daily, started at least 12 wk prior to onset of timothy grass pollen season, continued throughout season (has been taken daily for three consecutive years).

Availability

Sublingual tablets: 2800 bioequivalent allergy units (BAUs)

Assessment

• Assess for signs and symptoms of allergy (sneezing; runny or itchy nose; nasal congestion; itchy, watery eyes) before and periodically during therapy.
• Monitor for signs and symptoms of allergic reactions (trouble breathing, throat tightness or swelling, trouble swallowing or sleaking, dizziness or fainting, rapid or weak heartbeat, severe stomach cramps or pain, vomiting, diarrhea, severe flushing or itching) for at least 30 min after initial dose. Keep epinephrine, an antihistamine, and resuscitation equipment close by in the event of an anaphylactic reaction. Discontinue therapy of severe allergic reaction occurs. If persistent or escalating reactions occur, re-evaluate therapy and consider discontinuation.
• Monitor for signs and symptoms of eosinophilic esophagitis (severe or persistent gastro-esophageal symptoms, dysphagia, chest pain). Discontinue therapy and consider diagnosis if symptoms occur.
• Monitor for signs and symptoms of asthma attack (wheezing, coughing, dyspnea) before administering. Withhold if patient experiencing acute asthma exacerbation. If recurrent asthma exacerbations occur, consider discontinuation of therapy.
• Assess for oral inflammation (oral lichen planus, mouth ulcers, thrush) prior to administration. Allow healing before administration.

Potential Diagnoses

• Ineffective breathing pattern (Indications)

Implementation

• Therapy should be started at least 12 wks prior to onset and throughout grass pollen season. Administer first dose in health care setting and monitor patient for allergic reactions for at least 30 min. If no reactions occur, patient may administer subsequent doses at home.
• SL: Remove tablet from blister just prior to dosing. Immediately place tablet under tongue until complete dissolution for at least 1 min before swallowing. Wash hands after handling tablet.

Patient/Family Teaching

• Instruct patient in correct method of taking Grastek; avoid swallowing tablet until dissolved. Avoid food or beverage for 5 min after dissolution of tablet. If dose is missed, omit and take next scheduled dose next day; do not double doses. If more than 1 dose is missed, notify health care professional before restarting. Explain to patient that therapy does not give immediate relief of allergy symptoms. Instruct patient to read Medication Guide before starting therapy and with each Rx refill in case of changes.
• Instruct patient in how and when to use autoinjectable epinephrine and to seek immediate medical care if used.
• Advise patient to stop therapy notify health care professional if signs and symptoms of allergic reactions, asthma attack, oral inflammation, or eosinophilic esophagitis occur.
• Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care professional before taking other Rx, OTC, or herbal products.
• Advise female patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

Evaluation/Desired Outcomes

Decreased symptoms or allergic rhinitis and/or conjunctivitis.