Grazax

What Is Grazax?

Grazax is a sublingual immunotherapy tablet used to treat allergic rhinitis (hay fever) and conjunctivitis caused by grass pollen in adults and adolescents aged 5 years and over. It contains a standardised allergen extract of timothy grass pollen (Phleum pratense), which is the allergen responsible for most grass pollen allergy in Northern Europe. Unlike antihistamines and nasal corticosteroids, which only suppress allergy symptoms, Grazax works by gradually desensitising the immune system to grass pollen through a process of immunological tolerance — potentially offering long-term disease modification rather than simple symptom relief.

Grazax is taken as a once-daily tablet that dissolves under the tongue (sublingual administration). Small amounts of the grass pollen allergen are regularly introduced to the immune system via the mucosa of the mouth, training the immune system to tolerate grass pollen rather than react to it with an allergic response. Clinical trials have shown that Grazax significantly reduces both the severity of rhinitis symptoms and the need for antiallergy rescue medication during the grass pollen season.

Treatment Course and Timing

Grazax requires a commitment to a three-year treatment course for maximum benefit. The first tablet must be taken under medical supervision, as there is a risk of allergic reactions with the initial dose. Treatment should be started at least 4 months before the expected beginning of the grass pollen season — typically around March in the UK, with the pollen season running from May to July — to allow sufficient time for immunological tolerance to develop before pollen exposure begins. Patients with severe or uncontrolled asthma, recent anaphylaxis, or significant autoimmune disease are not suitable candidates for Grazax.

Long-Term Efficacy

Evidence from clinical trials indicates that the benefits of Grazax persist for at least 1 to 2 years after completion of the three-year course, suggesting genuine disease modification. This distinguishes sublingual immunotherapy from purely symptomatic treatments that provide no lasting benefit after they are stopped.

How to Take Grazax

Grazax tablets are taken by dissolving one tablet under the tongue (sublingually) once daily. The tablet should be placed under the tongue immediately after removing it from the blister pack, where it will dissolve within approximately 1 to 2 minutes. The liquid should be held under the tongue for 1 minute, then swallowed. Nothing should be eaten or drunk for the following 5 minutes after taking the tablet.

The first dose must always be administered in a healthcare setting (such as a clinic or pharmacy) under medical supervision, as there is a small risk of a systemic allergic reaction with the first exposure. Patients are usually observed for at least 30 minutes after the first dose. Subsequent doses can be self-administered at home. Grazax should be taken at the same time each day, and ideally on an empty stomach or at least 30 minutes away from meals, though this is not critical to efficacy.

During and Outside the Pollen Season

Grazax is taken continuously throughout the year — both during and outside the grass pollen season — for the full three-year course. Treatment should not be stopped during the pollen season, as consistency of allergen exposure is important for maintaining and building tolerance. If doses are missed, the course should be continued from where it was left off, but if a significant number of doses have been missed, patients should contact their allergy specialist for advice.

The dose of Grazax is one tablet (75,000 SQ-T) placed under the tongue once daily. There is no dose titration — the full therapeutic dose is used from the outset. The treatment course is 3 years of continuous daily dosing. Treatment should be initiated 4 months before the expected start of the grass pollen season to ensure adequate immunological preparation before the patient encounters significant grass pollen exposure. In the UK, this typically means starting treatment in January or February to be ready for the May-to-July pollen season. Grazax is approved for use in adults and children aged 5 years and over. In children, the same dose and administration method are used as in adults. Dose adjustment is not required based on age or body weight within the approved age range.

Grazax frequently causes local reactions in the mouth and throat, particularly in the first weeks of treatment as the oral mucosa adapts to the allergen. These reactions are generally mild and expected as part of the immunological process, and they typically diminish over time.

Common Side Effects

• Oral pruritus (itching of the mouth, lips, or tongue) — very common, especially in the first weeks of treatment
• Throat irritation or tightness in the throat
• Swelling of the lips, tongue, or inside the mouth (oral oedema)
• Tingling or burning sensation in the mouth
• Ear itching (due to connected mucous membranes)
• Sneezing or nasal congestion shortly after taking the tablet
• Mild nausea in some patients

Serious Side Effects

• Systemic allergic reaction (anaphylaxis): severe breathing difficulty, swelling of the throat, severe drop in blood pressure, loss of consciousness — this is rare but is the reason the first dose must be given under medical supervision; if symptoms of anaphylaxis occur after subsequent doses, call 999 immediately
• Severe asthma exacerbation triggered by the allergen in susceptible patients
• Significant worsening of allergic eye symptoms (conjunctivitis) shortly after taking the dose
• Generalised urticaria (hives) or extensive skin rash — rare; contact your doctor

Anaphylaxis and First-Dose Supervision

Grazax carries a risk of systemic allergic reactions, and the first dose must always be administered under medical supervision with access to emergency treatment (adrenaline). Patients with a history of severe anaphylaxis, severe or poorly controlled asthma (FEV1 below 70 percent predicted), or those experiencing acute asthma symptoms should not receive Grazax. Patients with oral inflammatory conditions such as aphthous ulcers, oral lichen planus, or following recent oral surgery should delay starting Grazax until the condition has resolved, as the integrity of the oral mucosa affects the safety and absorption of the allergen.

Antihistamines or anti-inflammatory mouthwashes can be used to manage local oral reactions, but systemic corticosteroids should be avoided as they may impair the immunological response to treatment.

Adrenaline Auto-Injector

Patients receiving Grazax should be prescribed an adrenaline auto-injector (such as an EpiPen) to carry at all times in case of a severe allergic reaction. They should be trained in its use and should ensure that family members or carers are also aware of how to administer it in an emergency. During the grass pollen season, patients may experience a temporary worsening of symptoms due to high ambient pollen levels, and may use antihistamines or nasal corticosteroids as rescue medication during this period.

Grazax is contraindicated in the following circumstances:

• Severe or uncontrolled asthma with an FEV1 below 70 percent of predicted value despite optimal pharmacological treatment
• History of severe or repeated episodes of anaphylaxis
• Active autoimmune disease (e.g., systemic lupus erythematosus, rheumatoid arthritis) where immune modulation is inappropriate
• Malignant or severe immunodeficiency conditions, or patients receiving immunosuppressive therapy
• Active or severe oral inflammation, including oral infections, ulcers, or recent oral surgery (until fully healed)
• Known hypersensitivity to any of the excipients in the Grazax tablet formulation
• Patients not able to tolerate adrenaline (e.g., severe cardiovascular disease, use of beta-blockers that may block adrenaline's effect in an emergency)
• Pregnancy: initiation of new immunotherapy treatment is not recommended during pregnancy, though it may be continued in established patients under specialist guidance