Health Library

Allergy antigen (By injection)

Treats an allergy by making your body less sensitive to the substance you are allergic to. After receiving this medicine for a time, you should either not have an allergic reaction or have a less severe reaction. Also used for allergy testing.

Brand Name(s):

When This Medicine Should Not Be Used:

How to Use This Medicine:

Injectable

• You should have allergy skin tests before you start a treatment plan with this medicine.
• Your doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given as a shot under your skin. The shot is usually given in your upper arm.
• A nurse or other health provider will give you this medicine.
• If you are allergic to more than one substance, you might need more than one injection during each visit to the doctor's office or clinic. You might need to wait up to 30 minutes between each injection.
• You will need to stay for as long as 30 minutes after you receive the injection.
• Before you receive an injection, always tell your health caregiver these things:
  • If you had any reactions to your previous allergy shot.
  • If you have missed any shots recently.
  • If you are having allergy symptoms, even from an allergy that is not part of this treatment.
  • If you are sick or have an infection, especially if you also have a fever.
  • If you have been stung recently by an insect.
• You will slowly receive larger doses of this medicine until you reach the maintenance dose. Once you are on the maintenance dose, you will slowly start having injections less often. Most people continue with a maintenance injection about once a month.

If a dose is missed:

• Call your doctor or treatment clinic for instructions.
• This medicine needs to be given on a regular basis. If you miss too many appointments, it will take longer for you to finish your treatment plan.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Make sure your doctor knows if you are also using a beta blocker medicine such as atenolol, carvedilol, labetalol, metoprolol, nadolol, propranolol, timolol, Blocadren®, Coreg®, Inderal®, Lopressor®, Tenormin®, or Toprol®. Beta blocker medicines can be used to treat several conditions, including high blood pressure, heart problems, or migraine headaches.

Warnings While Using This Medicine:

• Make sure your doctor knows if you are pregnant or breastfeeding.
• The medicine contains an allergen (the substance that you are allergic to). You will be given the allergen in small amounts, so your body will slowly get used to it. This means there is a small risk that you will have an allergic reaction to the medicine. Before you start a treatment plan with this medicine, talk with your doctor about this risk.
• Make sure you understand the signs and symptoms of an allergic reaction that needs treatment. Tell your health caregiver any time you think you are having a severe allergic reaction to this medicine. Some signs of a severe allergic reaction might be:
  • Dizziness, light-headedness, or fainting.
  • Fast, slow, or pounding heartbeat.
  • Hives, itching, or skin rash.
  • Sneezing, cough, watery eyes, and runny or stuffy nose.
  • Swelling around your mouth or inside your mouth or throat.
  • Wheezing or other trouble breathing.
• Talk to your doctor about what you should do if you have an allergic reaction after you leave the doctor's office. Some people need to carry special medicine (such as epinephrine, EpiPen®) to treat themselves.
• Many people have redness, heat, mild pain, or mild swelling where the shot was given. Ask your health caregiver what to do if you have this reaction. Many people can put ice on it or take an antihistamine, but your situation might be different.
• A small number of people will still have some kind of allergic reaction even after being treated with the medicine. However, the allergic reaction should be less severe and easier to manage than before.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Dizziness, light-headedness, or fainting.
• Fast, slow, or pounding heartbeat.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 9/6/2024