What is the first treatment for a drug allergy?

A reaction may involve a rash, itching, swelling, breathing difficulty, vomiting or dizziness. A clinician considers when symptoms began, the medicine and dose, other medicines, previous reactions and whether infection or another cause could explain the symptoms.

For a mild reaction, the suspected medicine may be replaced and symptoms treated with suitable medication. A severe, rapidly developing reaction can affect breathing or circulation and needs emergency treatment. Allergy testing is not always the first step during an active reaction; it may be arranged later to clarify which medicines should be avoided.

If you suspect a reaction, contact a clinician promptly and keep the medicine packet or prescription available. Do not take another dose until a qualified professional tells you what to do, unless it is a critical medicine and stopping it could be dangerous; in that situation, seek urgent advice immediately.

Write down the medicine name, timing and symptoms. Do not challenge yourself with the suspected medicine. Ask for the reaction to be recorded clearly in your medical record, including the symptoms rather than only the word allergy.

Call emergency services for swelling of the lips, tongue or throat, wheezing, trouble breathing, faintness, confusion or a rapidly spreading reaction. Lie down if you feel faint while waiting for help, unless breathing is easier sitting up. A severe reaction can worsen quickly even if the first symptoms seem manageable.

Ask whether the medicine should be stopped, which alternatives are safe, whether you need an emergency plan, and whether allergy testing could clarify future treatment choices. Ask how to describe the reaction to pharmacists and other clinicians.