Yes. A serious allergic reaction can happen around the time of a general anaesthetic, and it is called anaphylaxis. It is rare, but it can be life threatening. It often happens very quickly. Signs can include a fall in blood pressure, breathing trouble, swelling, and skin rash. The medicines that usually cause this kind of reaction include antibiotics, muscle relaxants used for some surgery, and sometimes antiseptics or dyes.

If you have had an allergic reaction before, it is not routine to have allergy tests before surgery, but you should be referred to a specialist clinic for testing after a serious reaction. If a medicine is found to be the cause, you should not have that medicine again, and you may need to avoid similar medicines too. Bring any allergy clinic letter with you to future visits.

Tell your nurse or anaesthetist about any allergy you have, and bring a list of allergies to the hospital and on the day of surgery.