Safety notes

Safety facts from product labels that can't be indexed, restated and checked by a clinician. Each note lists its source. Answers name the note and link this page.

  • Azathioprine and mercaptopurine with allopurinol · Interaction

    Allopurinol inhibits xanthine oxidase, which breaks down azathioprine and mercaptopurine. When allopurinol is co-prescribed, the UK product labels reduce the azathioprine or mercaptopurine dose to one quarter of the usual dose, with close blood-count monitoring.

    Source: UK SmPC for azathioprine or mercaptopurine, section 4.5 Interactions. Added 7 November 2026.

  • Etoricoxib · Contraindication

    The UK product label for etoricoxib lists inflammatory bowel disease as a contraindication.

    Source: UK SmPC for etoricoxib (Arcoxia), section 4.3 Contraindications. Added 7 November 2026.