Adverse Drug Reaction
Medically reviewed by Drugs.com. Last updated on May 4, 2025.
An adverse drug reaction is a harmful reaction to a medicine given at the correct dose. The reaction can start soon after you take the medicine, or up to 2 weeks after you stop. An adverse drug reaction can cause serious conditions such toxic epidermal necrolysis (TEN) and anaphylaxis. TEN can cause severe skin damage. Anaphylaxis is a sudden, life-threatening reaction that needs immediate treatment. Ask your healthcare provider for more information on TEN, anaphylaxis, and other serious reactions.
DISCHARGE INSTRUCTIONS:
Call 911 for signs or symptoms of anaphylaxis,
such as trouble breathing, swelling in your mouth or throat, or wheezing. You may also have itching, a rash, hives, or feel like you are going to faint.
Return to the emergency department if:
- Your heart is beating faster than usual.
- You are more tired than usual, and you are shivering.
- Your skin is blistering or peeling.
- One of your pupils becomes larger than usual, and does not return to normal.
Contact your healthcare provider if:
- You start a new medicine and develop a fever.
- You have an itchy rash.
- Your rash returns after treatment has stopped.
- You have questions or concerns about your condition or care.
Medicines:
- Epinephrine is used to treat severe allergic reactions such as anaphylaxis.
- Antihistamines decrease mild symptoms such as itching or a rash.
- Steroids are given to decrease swelling. Steroids may be given as a pill or a skin cream.
- Take your medicine as directed. Contact your healthcare provider if you think your medicine is not helping or if you have side effects. Tell your provider if you are allergic to any medicine. Keep a list of the medicines, vitamins, and herbs you take. Include the amounts, and when and why you take them. Bring the list or the pill bottles to follow-up visits. Carry your medicine list with you in case of an emergency.
Follow up with your healthcare provider as directed:
Write down your questions so you remember to ask them during your visits.
Steps to take for signs or symptoms of anaphylaxis:
- Immediately give 1 shot of epinephrine only into the outer thigh muscle.
- Leave the shot in place as directed. Your healthcare provider may recommend you leave it in place for up to 10 seconds before you remove it. This helps make sure all of the epinephrine is delivered.
- Call 911 and go to the emergency department, even if the shot improved symptoms. Do not drive yourself. Bring the used epinephrine shot with you.
Safety precautions to take if you are at risk for anaphylaxis:
- Keep 2 shots of epinephrine with you at all times. You may need a second shot, because epinephrine only works for about 20 minutes and symptoms may return. Your healthcare provider can show you and family members how to give the shot. Check the expiration date every month and replace it before it expires.
- Create an action plan. Your healthcare provider can help you create a written plan that explains the allergy and an emergency plan to treat a reaction. The plan explains when to give a second epinephrine shot if symptoms return or do not improve after the first. Give copies of the action plan and emergency instructions to family members, work and school staff, and daycare providers. Show them how to give a shot of epinephrine.
- Be careful when you exercise. If you have had exercise-induced anaphylaxis, do not exercise right after you eat. Stop exercising right away if you start to develop any signs or symptoms of anaphylaxis. You may first feel tired, warm, or have itchy skin. Hives, swelling, and severe breathing problems may develop if you continue to exercise.
- Carry medical alert identification. Wear medical alert jewelry or carry a card that explains the medication allergy. Healthcare providers need to know that they should not give you this medicine. Ask your healthcare provider where to get these items.
- Read medicine labels before you use any medicine. Do not take anything that contains the medicine you are allergic to. This includes topical medicines that you put on your skin. Ask a pharmacist if you are not sure.
- Tell all healthcare providers about your allergy. Include the names of medicines you are allergic to and the symptoms of your allergic reactions.
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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.
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