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Medicines allopurinolQuestion & answer

allopurinol · Medicine question

Why can gout attacks happen after starting allopurinol?

iatroX medicinesMedicine guide reviewed 13 August 2026

The answer

Answer

Changing uric acid levels can temporarily mobilise existing crystals and trigger flares. This does not necessarily mean the medicine is failing.

Sources for this answer

Allopurinol Tablets BP 100mg — Current selected SmPCemc · Summary of Product Characteristics
Allopurinol 100mg — Current selected SmPCemc · Summary of Product Characteristics
NHS

NHS · NHS medicine guidance

General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.

The full medicine guide

allopurinol

Read the wider context, including uses, precautions and the sources behind this medicine guide.

Read the allopurinol guide

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More questions about allopurinol

Does allopurinol relieve gout-attack pain?Should I stop allopurinol if I develop a rash?Can allopurinol affect the kidneys?Can allopurinol affect the liver or blood cells?Can I take allopurinol with azathioprine or mercaptopurine?Can I take amoxicillin with allopurinol?