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This page is for adults and children aged 5 and older who have been prescribed GRAZAX® to treat grass pollen allergy. It explains how the treatment works, how to take it safely, possible side effects and when to get help. It supports the advice from your allergy team. Ensure you have also read the Patient Information Leaflet (PIL) that is inside your medication pack.

What is GRAZAX®

GRAZAX® is a sublingual immunotherapy tablet. This means the tablet is placed under the tongue. Immunotherapy helps your body get used to grass pollen over time.

How does it work

Each tablet gives your body a set amount of grass pollen to help your immune system become less sensitive to it. You should start taking the medication 2 to 4 months before the grass pollen season starts. You should then keep taking it every day all year round.

The usual dose is one tablet each day. Most people keep taking GRAZAX® for 3 years to get long-lasting results. If there is no improvement after 12 months, speak to your allergy team. Keep taking your other allergy or asthma medicines unless told otherwise.

Who should avoid GRAZAX®

GRAZAX® is not recommended for individuals with the following conditions:

  • If you have severe asthma.
  • If you have swelling or inflammation of the mouth.
  • If you have severe mouth ulcers.
  • If you have an illness that affects the immune system.
  • If you have cancer.
  • If you have a severe fish allergy as this medication contains fish gelatine.

Tell your doctor:

  • If you recently had dental work or lost a tooth. You may need to pause treatment until the wound heals.
  • If you have reacted badly to allergy injections before.
  • If you have an autoimmune disease.
  • If you are pregnant or planning a pregnancy.
  • If you have asthma.
  • If you have a current chest infection.
  • If you are planning to have any vaccinations. You can usually continue taking GRAZAX® after a medical review.

How to take GRAZAX®

First dose in clinic

Your first dose will be taken in the clinic so that the clinical team can monitor you. The clinical team will check your observations, this may include your pulse, blood pressure and peak flow. You will stay in the department for one hour for observation. We advise you to take a non-drowsy antihistamine one to two hours before your first dose and for the next couple of weeks of treatment. This is to help reduce the local mouth symptoms you may experience.

Daily at home

  1. Make sure your fingers are dry before removing the tablet.
  2. Place the tablet under your tongue; it dissolves quickly.
  3. Avoid swallowing for 1 minute.
  4. Do not eat or drink for 5 minutes after the dose.
  5. Take 1 tablet once daily at about the same time.

If you missed a dose, you can take it later on the same day. Do not take two tablets on the same day. If you miss more than 7 days in a row, contact your clinic or GP.

Common side effects

In the first week of treatment it is common to see:

  • Itching in the mouth or ears.
  • Swelling in the lips or mouth.
  • Throat irritation.
  • Sneezing.
  • Stomach pain or vomiting.

If you have experienced any of the symptoms above, an antihistamine may help. If you are unsure you can ask your clinical team for advice.

When to seek urgent medical help

Go straight to the emergency department or ring 999 if you develop:

  • Sudden worsening of your asthma.
  • If you are having breathing trouble.
  • If you have any swelling of the face, mouth or throat.
  • If you have voice changes.
  • If you have throat tightness or are having trouble swallowing.
  • If you have a rash.
  • If you feel faint or you have fainted.
  • If you have a severe allergic reaction.

You can report any side effects using the website below.

Yellow Card

Website: www.yellowcard.mhra.gov.uk

Pregnancy and breastfeeding

Do not start GRAZAX® during pregnancy. If you become pregnant while on treatment, contact your team. It may be possible to continue with your treatment after you have spoken to your clinical team.

There is no clinical data to say you cannot take this medication when breastfeeding.

Monitoring and follow-up

Your first dose is supervised in the clinic with observations and at least one hour of monitoring. You may be asked to phone or email the department in the first few days to report early side effects. You will then be reviewed annually by the allergy team. Your GP will continue prescribing and may review you between hospital appointments.

Benefits

  • Less allergy symptoms and flare-ups.
  • It may reduce the need for other allergy medicines.
  • It is possible to achieve long-term control after 3 years.

Risks

  • You may have more mouth and throat reactions.
  • You may experience a serious allergic reaction, though this is rare.
  • Your asthma may worsen.

Alternatives

  • You can continue using nasal sprays or antihistamines.
  • Avoid grass pollen exposure.
  • Other immunotherapy options may be available. Please ask your clinical team.

Practical Tips

Start taking this medicine 2 to 4 months before the pollen season starts. Take your tablet at the same time every day. It may be helpful to link it to your routine, such as after brushing your teeth. You may also find it helpful to set a reminder on your mobile device. It is important that you do not share your tablet and store it as described in the PIL.

Contact information

Allergy Clinic

Tel: 0300 422 6187

Monday to Friday, 09:00 am to 17:00 pm

Allergy Secretaries

Email: natasha.hill3@nhs.net

Out of hours or urgent care

NHS 111

Accessibility and formats

If you need this information in another language, large print, Braille or audio, please let the clinic know. The hospital can provide information in alternative formats that comply with accessibility standards.

Printable version of this page

GRAZAX GHPI1939_12_25 Department: Ear, Nose and Throat Review due: December 2028 PDF, 170.9 KB, 8 pages