Any medication has the potential to cause non-allergic side effects, but some people can also have allergic reactions to specific medication. All medication, including prescription medication or over-the-counter medication bought from supermarkets and pharmacies, can trigger allergies in some people, but some types are more likely to cause allergies than others.

Allergies are not the same as the non-allergic side effects that are listed in Consumer Medicine Information (CMI) sheets for prescription medication.

The CMI includes detailed information about the medication in plain English, including use, side effects and precautions. Your pharmacist can give you the CMI for your medication. You should also ask your pharmacist for advice if you buy over-the-counter medication.

They can advise you about side effects and possible interactions with other medication you are taking. Any medication could cause an allergic reaction, but some are more likely to than others, including: Of these types, the two that commonly cause allergic reactions are aspirin and similar pain-relieving medication, and sulfonamide antibiotics.

Severe allergic reaction, also known as anaphylaxis, after taking a medication is life threatening.

Symptoms of a severe allergic reaction include:

  • Milder allergic symptoms that can occur before a severe allergic reaction include
  • If you have experienced any of these symptoms after taking a medication
  • you are at greater risk of having another severe reaction when you take the same medication. Most people with these allergies are allergic to only one medication
  • but some people are allergic to more than one

You should ask your doctor to refer you to a medical specialist (allergist/clinical immunologist).

If you are at risk of a severe allergic reaction, you should: wear medical identification jewellery – this increases the likelihood that adrenaline will be administered in an emergency avoid medication (where possible) that may increase the severity of allergic reaction or complicate its treatment – such as beta blockers Emergency responses for a severe allergic reaction are:

  • Aspirin belongs to a group of medications called NSAIDs that help to reduce fever
  • pain inflammation

Side effects of high doses of aspirin that are not caused by allergies include bruising and stomach upset, but even higher doses can cause confusion and ringing in the ears. Allergic symptoms are different to these side effects and range from milder symptoms to anaphylaxis.

If you already have allergic conditions such as hives, hay fever symptoms or asthma, you are more likely to develop an allergy to aspirin or other NSAIDs than people who do not have these symptoms. Sulfonamide antibiotics can cause allergic reactions, ranging from mild or severe rashes to anaphylaxis.

Several sulfonamide antibiotics are available with a prescription in United States, either alone or in combination with another type of antibiotic.

If you have an allergic reaction after taking a combination antibiotic, you should visit your doctor to talk about which antibiotic is causing your allergy. Allergic reactions to sulfonamide antibiotics do not make it more likely that you will be allergic to sulfur powder, sulfite preservatives, or non-antibiotic sulfonamide medication, such as pain-relievers or water tablets (diuretics).

Once you have taken a medication and it is circulating in your blood, you can have a generalised allergic reaction within hours.

Symptoms include:

  • Some allergic reactions to medication can occur days or weeks after you begin taking them
  • even continue after you have stopped taking them. These symptoms may include: If you think you may have an allergy to a medication
  • keeping a record (diary) of your symptoms can help you
  • your doctor to understand what is causing your symptoms

In your diary, also include whether your symptoms occur: after you have taken a particular medication, either prescription or over the counter from a pharmacy or supermarket If you have allergic symptoms after taking medication, you should visit your family doctor who will ask some questions about your symptoms.

Your diary will help you to answer these questions accurately.

To diagnose your allergy, your doctor will refer you to a specialist doctor known as an allergist or clinical immunologist. Allergists can test for allergies using a number of methods, depending on the type of potential allergy.

The allergist can test for allergies to some medication using a skin prick test or a blood test. Testing and treating allergies and hypersensitivities to medication can be difficult and allergists can also use: graded challenge – four to five progressively larger doses of the medication are given up to the desired dose and any symptoms are recorded desensitisation treatment – begins with a very small dose and then the dose progressively increases over hours to days, with the aim of ‘switching off’ the allergic reaction to the medication A number of methods claim to test for allergies but have not been medically or scientifically proven.

They can be costly and could lead to dangerous avoidance of certain foods.

The organisation representing allergists (American Society of Clinical Immunology and Allergy) recommends that you do not use certain methods to have potential allergies tested, including: Always speak with your doctor if you are thinking of using a complementary medicine or therapy to test for allergies.

Skin or blood allergy tests are not available to test for aspirin allergies.

If your doctor needs to know whether you have sensitivity to aspirin (or an NSAID), you may have a graded challenge test under strict medical supervision.

Skin allergy tests are available for sulfonamide antibiotic allergies and can be used when you have had an allergic reaction to combination antibiotics. Once doctors know which antibiotic is causing your allergy, they can recommend the one you should avoid and which antibiotics you can take. One strategy for allergies to medication is to manage the problem by avoiding that medication.

In some situations, this can be difficult, especially if you have a chronic condition such as arthritis that needs ongoing treatment. Other approaches that can be used include:

  • Tel. Causes of allergies to medication aspirin
  • non-steroidal anti-inflammatory drugs (NSAIDs) antibiotics – penicillin
  • floppiness in young children swelling of the lips
  • eyes hives or welts tingling mouth abdominal pain
  • other pain-relieving medication Allergies to sulfonamide antibiotics Symptoms of generalised allergies to medication skin rash or hives itchy skin fever swelling runny nose itchy
  • watery eyes shortness of breath wheezing serum sickness – fever
  • joint pain rash
  • swelling nausea anemia caused by medication – tiredness shortness of breath
  • irregular heartbeat rash – swelling
  • swollen lymph nodes or the return of a previous hepatitis infection inflammation of the kidneys (nephritis) – fever
  • blood in the urine swelling
  • confusion Diagnosis of allergies to medication for a short time or longer – how long the symptoms lasted at night
  • always call 911 Emergency department of your nearest hospital NURSE-ON-CALL (616) 555-0024 – for expert health information
  • advice (24 hours
  • days) Medicines Line (United States) Tel

1300 MEDICINE ( (616) 555-0400 ) – for information on prescription, over-the-counter and complementary medicines St John Ambulance United States (Michigan) Tel. (616) 555-0400 Allergy and Anaphylaxis United States Tel. (616) 555-0400.