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Allergen immunotherapy Pregnancy: Section 4.6: 'There is no data on the clinical experience for the use of Grazax in pregnant women. Animal studies do not indicate increased risk to the foetus. Treatment with Grazax should not be initiated during pregnancy. If pregnancy occurs during treatment, the treatment may continue after evaluation of the general condition (including lung function) of the patient and reactions to previous administration of Grazax. In patients with pre-existing asthma close supervision during pregnancy is recommended.' Breastfeeding: 'No clinical data are available for the use of Grazax during lactation. No effects on the breastfed infants are anticipated.' Fertility: 'There is no clinical data with respect to fertility for the use of Grazax. In mice, there was no effect on mating or fertility with Grazax treatment (see section 5.3).'

Grass pollen extracts

Brand names: Grazax (sublingual), Pollinex (SC)

Grass pollen extracts are standardised allergen preparations used for allergen immunotherapy (desensitisation) in patients with grass-pollen-driven allergic rhinoconjunctivitis, available as sublingual or subcutaneous formulations.

Adult dose

Dose: Disease-modifying treatment of grass pollen induced rhinitis and conjunctivitis, with clinically relevant symptoms and a positive skin prick test and/or specific IgE test to grass pollen - Grazax: Adults: one sublingual lyophilisate (75,000 SQ-T) daily.
Route: Sublingual (lyophilisate placed under the tongue, where it disperses). The first sublingual lyophilisate is recommended to be taken under medical supervision (20-30 minutes). Specialist-initiated: 'Grazax treatment should only be initiated by physicians with experience in treatment of allergic diseases and the capability to treat allergic reactions.'
Frequency: Once daily. For clinical effect in the grass pollen season, start at least 4 months before the expected start of the grass pollen season and continue throughout the season (if started 2-3 months before the season some efficacy may also be obtained). For long-term efficacy and disease-modifying effect, continue daily treatment for 3 consecutive years. If no relevant improvement of symptoms is observed during the first pollen season, there is no indication for continuing the treatment.
PRODUCT AND SCOPE: this entry reproduces the UK SPC for ONE product only - Grazax 75 000 SQ-T sublingual lyophilisate (standardised allergen extract of grass pollen from Timothy, Phleum pratense; 75,000 SQ-T per sublingual lyophilisate, SQ-T = Standardised Quality units Tablet; Phl p 5 content 6 micrograms on average per lyophilisate - SPC section 2). The page also lists a subcutaneous product (Pollinex, SC); the SPC covers the SUBLINGUAL route only, so subcutaneous grass-pollen schedules and any other allergen product, unit or schedule are not covered here. ADMINISTRATION (SPC 4.2): take the lyophilisate from the blister unit with dry fingers and place it under the tongue, where it will disperse; avoid swallowing for about 1 minute; do not take food or beverage for the following 5 minutes; take it immediately after opening the blister. SPECIAL POPULATIONS: elderly - clinical experience in those 65 years or older is lacking; children younger than 5 years - clinical experience is lacking (see paedDose); for treatment of children, physicians should be experienced in treating allergic diseases in children. SPC 4.4 points that affect the regimen: in case of oral surgery, including dental extraction, and shedding of a deciduous tooth in children, stop Grazax for 7 days to allow healing of the oral cavity; in patients with asthma and an acute respiratory tract infection, postpone initiation until the infection has resolved; in patients with severe or persisting gastro-oesophageal symptoms such as dysphagia or dyspepsia, discontinuation should be considered (eosinophilic oesophagitis reported); if patients with concomitant asthma have signs of asthma deterioration, treatment should be discontinued and a physician consulted immediately. Some sections of the product information we used were incomplete — check the full SPC. The SPC prints no maximum dose.

Paediatric dose

Dose: Children 5 years or older (grass pollen induced rhinitis and conjunctivitis): one sublingual lyophilisate (75,000 SQ-T) daily - the same dose as adults (SPC: 'The recommended dose for adults and children (5 years or older) is one sublingual lyophilisate (75,000 SQ-T) daily').
Route: Sublingual (placed under the tongue)
Frequency: Once daily, as for adults
SPC: clinical experience on immunotherapy with Grazax in children younger than 5 years is lacking, so no dose is given for them. Physicians treating children should be experienced in treating allergic diseases in children. Patients with uncontrolled or severe asthma (children: FEV1 < 80% of predicted value after adequate pharmacologic treatment) should not be treated with Grazax. In case of shedding of a deciduous tooth, stop Grazax for 7 days to allow healing of the oral cavity.

Dose adjustments

Renal

Not stated in the product information we used — check the full SPC.

Hepatic

Not stated in the product information we used — check the full SPC.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via MHRA Products — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to any of the excipients (SPC section 6.1)
  • Malignancy or systemic diseases affecting the immune system, e.g. autoimmune diseases, immune complex diseases or immune deficiency diseases
  • Inflammatory conditions in the oral cavity with severe symptoms such as oral lichen planus with ulcerations or severe oral mycosis
  • Uncontrolled or severe asthma (in adults: FEV1 < 70% of predicted value after adequate pharmacologic treatment; in children: FEV1 < 80% of predicted value after adequate pharmacologic treatment)

Side effects

  • Mild to moderate local allergic reactions early in therapy that tend to subside spontaneously within 1 to 7 days; most commonly oral pruritus, throat irritation and oedema mouth, usually starting within 5 minutes of each dose
  • Very common: ear pruritus, throat irritation, oral pruritus, oedema mouth
  • Common: eye pruritus, conjunctivitis, eye swelling; sneezing, cough, dry throat, dyspnoea, oropharyngeal pain, pharyngeal oedema, rhinorrhoea, throat tightness, nasal pruritus; lip swelling, oral discomfort, paraesthesia oral, stomatitis, dysphagia, abdominal pain, diarrhoea, dyspepsia, nausea, vomiting, oral mucosal erythema, mouth ulceration, oral pain, lip pruritus; pruritus, urticaria, rash; fatigue, chest discomfort
  • Uncommon: anaphylactic reaction, systemic allergic reaction; dysgeusia, paraesthesia; palpitations; angioedema, erythema; laryngeal oedema, dysphonia; sensation of foreign body
  • Rare: eosinophilic oesophagitis, bronchospasm, ear swelling
  • Post-marketing: serious anaphylactic reactions, in some cases at doses subsequent to the initial dose

Interactions

  • No studies investigating drug interactions have been conducted in humans (SPC 4.5)
  • Concomitant symptomatic anti-allergic agents (antihistamines, corticosteroids and/or mast cell stabilisers) may increase the patient's tolerance level to immunotherapy
  • Limited data on the risks of simultaneous immunotherapy with other allergens during treatment with Grazax
  • Adrenaline for serious anaphylactic reactions: consider whether the patient would tolerate adrenaline (e.g. treatment with tricyclic antidepressants, MAOIs, COMT inhibitors and/or beta-blockers)
  • Simultaneous vaccination: clinical experience is missing; vaccination may be given without interrupting Grazax after medical evaluation of the patient's general condition

Monitoring

  • First sublingual lyophilisate recommended under medical supervision for 20-30 minutes, so that side effects and possible actions can be discussed
  • Review symptom improvement during the first pollen season; no indication to continue if no relevant improvement
  • Patients with asthma must be told to seek medical attention immediately if their asthma deteriorates suddenly; Grazax has not been studied in severe and uncontrolled asthma
  • Patients who previously had a systemic reaction to grass subcutaneous immunotherapy may be at increased risk of a severe reaction - consider initiation carefully and have measures to treat reactions available
  • Patients with cardiac disease may be at increased risk in severe systemic allergic reactions; clinical experience in cardiac disease is limited
  • Awareness when initiating in severe fish-allergic patients (Grazax contains fish-derived gelatine)
  • Consider anti-allergic medication (e.g. antihistamines) for significant local adverse reactions

Clinical monograph

How it works

Repeated controlled exposure to the allergen induces immune tolerance, shifting the response away from allergen-specific IgE and promoting regulatory T-cell activity and blocking IgG antibodies.

Prescribing in practice

  • Carries a risk of systemic allergic reactions including anaphylaxis, so initiation (particularly subcutaneous products) must occur where resuscitation facilities and trained staff are immediately available, with a period of observation after dosing.
  • Should be initiated and supervised by clinicians experienced in allergen immunotherapy, with treatment typically started before the pollen season and continued for a prolonged course.
  • Caution or avoidance in poorly controlled or severe asthma, which increases the risk of serious systemic reactions; refer to the SPC for the specific product.

Monitoring

Monitor for local and systemic allergic reactions during and after administration, with closer observation at initiation and after dose escalation.

Counselling the patient

  • You may notice itching or swelling in the mouth or at the injection site, which usually settles as treatment continues.
  • Seek urgent help if you develop widespread rash, breathlessness, wheeze, or facial swelling.
  • Benefit builds gradually and the full course must be completed for lasting effect.

Evidence & guidelines

Allergen immunotherapy for allergic rhinitis is supported by international allergy guidelines and is recognised by NICE as a treatment option for selected patients with severe, persistent symptoms uncontrolled by standard therapy.

Reference: BSACI immunotherapy guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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