Drug Allergy

You have been given this information leaflet because you have experienced an allergic reaction to a medication.

It is important that you and/or your carer know the name of the drug to avoid in the future. There may be related drugs that you also need to avoid. This will be explained to you and/or your carer.

What is an allergic reaction?

A drug allergy occurs when your immune system responds to the drug as if it were a harmful substance, instead of a helpful treatment. Your immune system creates antibodies to attack the medication. Chemicals released by your immune system can cause the signs and symptoms associated with an allergic reaction.

Signs and symptoms

The most common symptoms of a drug allergy are skin rashes and hives. Other allergic reactions which can occur include itchy eyes or skin, wheezing or swollen lips, tongue and face, or a combination of these.

The most serious type of reaction is an anaphylactic reaction, which is rare, but can be life-threatening. An anaphylactic reaction can cause the airways to constrict, making breathing very difficult. The blood pressure can lower and you may feel dizzy or faint.

Other signs and symptoms include slurred speech, rapid or weaker pulse rate or blueness of skin, lips and nail beds.

Always seek immediate medical care if you think you or someone else is having an anaphylactic reaction.

Treatment of allergic reactions

If you have experienced an allergic reaction to a medication, it will usually be stopped and avoided in the future.

The treatment for signs and symptoms depends on what kind of reaction you have. Rashes or hives may improve when treated with an antihistamine such as chlorpheniramine (Piriton®).

Anaphylaxis can be life threatening and requires an injection of epinephrine (adrenaline), additional close monitoring and care.

You may be referred to a specialist allergy clinic, so your allergy can be further investigated.

What should I do?

It is advisable to avoid the drug to which you have an allergy. Make sure that you and/or your carer know the name of the drug or drug class to which you are allergic, when you had a reaction and what type of reaction you experienced.

When you visit your doctor, make sure they are aware of any allergies before they prescribe any medicines for you.

When you visit your community pharmacy, make sure they are aware of any allergies before you buy any medicines over the counter and also when they give you any medicines prescribed by your doctor.

You may choose to wear a medical alert bracelet that identifies your drug allergy in an emergency situation. Ask for further information at your community pharmacy or GP surgery.

Useful contacts

If you have any further questions about your discharge medicines after you have left the hospital please telephone the hospital pharmacy on 01305 255294, Monday to Friday, 9am to 5pm or speak to your community pharmacist.

Drug allergy information

(to be completed by a registered healthcare professional)

Name:

Date of Birth:

Hospital Number

The above named patient has had an allergic reaction to:

Name of drug (generic):

Name of drug (proprietary/band):

Related drugs to avoid:

Date of reaction:

Type of reaction:

Treatment received:

Advice given:

Completed by (name):

Role:

Signature:

Date:

About this leaflet

Author: Christine Dodd, Deputy Chief Pharmacist and Medicines Safety Officer
Written: March 2019, updated August 2020
Updated and approved: March 2024
Review date: March 2027
Edition: v3

If you have feedback regarding the accuracy of the information contained in this leaflet, or if you would like a list of references used to develop this leaflet, please email patientinformation.leaflets@dchft.nhs.uk