Overview
- Patients are told to call 999 for chest pain that does not ease within minutes, and for angina pain that is new or worse than usual.
- The NHS advises a 999 call for severe allergic symptoms such as throat tightness, breathing difficulty, fainting, sudden swelling, or blue or pale skin.
- People are told not to drive themselves to A&E, and the 999 call handler will advise on next steps.
- Serious but non‑life‑threatening problems such as severe stomach pain or yellowing eyes should prompt contact with a GP or NHS 111.
- The NHS notes that serious adverse effects are uncommon at about one in 10,000, while mild effects like headaches, dizziness and a racing heartbeat affect more than one in 100.