Drug challenge in the allergy clinic (1308)

What is a drug challenge?

This procedure is done to see if a patient can take a medicine that caused a reaction in the past.

When is a drug challenge done?

• When medicine is needed to treat a condition.
• If history suggests a penicillin allergy and recent allergy testing was negative.

Why is it done in the clinic?

• There is a risk for allergic reaction. The clinic has supplies and staff to treat a reaction.

What happens during a clinic drug challenge?

• Questions will be asked and an exam will be done.
• There will be a breathing test if the patient has asthma or breathing problems.
• The patient will take a full dose of medicine during the challenge.  There are 2 ways this may be done.

1.  The patient will take a small amount of the medicine. If there is no reaction after 30 minutes, a larger amount will be given. The patent will then wait up to 60 minutes and we will watch for any reaction.  Or
2. The patient will take a full dose of medicine in one dose.  Then they will be watched for 45 to 60 minutes.

• A clinic drug challenge may last up to 2 to hours.

How do I prepare for a drug challenge?

• The clinic will supply the medicine.
• Keep taking all of your daily medicines. Do not stop asthma medicines.
• Bring activities or a book to read. You may also bring a drink.

Who should not have a drug challenge?

A drug challenge should not be done:

• If there is a history of serious or life-threatening reaction to the drug.
• When you are sick or have coughing, wheezing or breathing problems. Albuterol may be used for exercise or activity within 3 days of the challenge. Call the clinic if it has been used in the last 3 days. The patient may need to reschedule. This is done for the patient’s safety.
• If the patient is taking beta blocker medicines for high blood pressure, migraine headaches, or eye drops for glaucoma. Common names are: Propranolol, Metoprolol, Atenolol, Timolol or Betaxolol. Please talk with your health care provider about this before the challenge. 

What are the risks?

Mild reactions may happen during or after the challenge. They include:

Rash, a few hives, eczema that gets worse, diarrhea, sneezing, stuffy nose, runny nose, a change in behavior or a headache.

Serious reactions do not happen often, but they can lead to death if not treated. Tell the nurse right away if you have any of the following:

• Hives. Rash, swelling or itching of more than one part of the body.
• Swelling. Any part of the body, inside or out. This includes the mouth, tongue or throat. It can be one or many parts of the body.
• Breathing problems. Shortness of breath, coughing, wheezing or chest feeling tight.
• Other. Constant sneezing, feeling dizzy, stomach ache, nausea or just not “feeling right.”
• Anaphylactic shock is the most serious allergic reaction. It can be a combination of any of the above symptoms and can be life threatening. It can happen in a few minutes or up to 24 hours after the medicine has been given. It is important to watch for anaphylaxis, but it is does not happen often.

Call 9-1-1 if any of these symptoms happen after leaving the clinic!

What happens if the patient has a reaction?

• If the patient has a reaction, the challenge is stopped.
• The patient will need to continue to avoid that medicine.
• If there is a serious or anaphylactic reaction, emergency medicine will be given right away. The medicine is called epinephrine and comes in an Epinephrine Auto-injector.
• By signing the consent form for the challenge, permission has been given to do a drug challenge and treat any reaction.

What happens after a clinic drug challenge?

• Watch for a delayed reaction.
• If there is a reaction at home take medicine to treat the reaction. Go to the emergency room if needed. Call the Allergy Clinic with any questions: 414-266-6450.
• If there is a reaction to the medicine, the patient will need to continue to avoid it. Some medicines are part of a larger family or class of drugs and all related medicines may also need to be avoided.
• If there is no reaction during the challenge, the medicine can be used as directed by your provider. The medicine will be taken off of the patient’s allergy list.