How should I manage a patient who has experienced an adverse drug reaction to a medication they are currently taking?

When managing a patient who has experienced an adverse drug reaction (ADR) to a medication they are currently taking, the first step is to assess the reaction carefully by taking a detailed history and performing a clinical examination to determine the likelihood that the drug caused the reaction and to classify the type of reaction (immediate or non-immediate, allergic or non-allergic) ². If drug allergy is suspected, consider stopping the suspected drug immediately and advise the patient to avoid it in the future ². Treat any acute symptoms as needed, and for severe reactions such as anaphylaxis or severe cutaneous adverse reactions (e.g., Stevens-Johnson syndrome, DRESS), urgent hospital referral is required ².

Document the suspected drug allergy thoroughly in the patient’s medical records, including the drug name, nature of the reaction, and any investigations performed ². Provide the patient with clear, structured written information about their suspected drug allergy, including drugs or drug classes to avoid and advice to check with a pharmacist before taking any over-the-counter medicines ². Advise patients to carry this information at all times and share it with healthcare professionals when prescribed or administered any medication ².

Involve a pharmacist with relevant clinical expertise to support medicines optimisation and ensure safe future prescribing ¹. Referral to a specialist drug allergy service is recommended if the patient has had a suspected anaphylactic reaction or a severe non-immediate cutaneous reaction ². Specialist assessment may include allergy testing to confirm or exclude the diagnosis and to identify safe alternative drugs ².

Recent literature on managing hypersensitivity reactions to specific drug classes, such as anti-tuberculosis drugs, supports this approach by emphasizing early recognition, withdrawal of the offending agent, symptomatic treatment, and specialist referral for complex cases (Bermingham et al., 2022). This aligns with the UK guidelines but highlights the importance of tailored management depending on the drug involved and the reaction severity.

In summary, management involves prompt recognition, stopping the suspected drug, symptom treatment, documentation, patient education, pharmacist involvement, and specialist referral when indicated ¹,² (Bermingham et al., 2022).