Nothing to eat or drink – fasting (‘Nil by mouth’)

The hospital should give you clear instructions about fasting. It is important to follow these. If there is any food or liquid in your stomach during your anaesthetic, it could come up into the back of your throat and then go into your lungs.

This would cause choking, or serious damage to your lungs.

The times you need to fast is

  • 6 hours for food
  • 4 hours for breast milk
  • 2 hours for water

In an emergency (such as needing surgery for badly broken bones), where people have not had time to fast, there are other techniques and drugs that allow anaesthesia to be given safely which your anaesthetist will explain to you.

Your normal medicines

You should continue to take your normal medicines up to and including the day of surgery, unless your anaesthetist
or surgeon has asked you not to. Morning medications are to be taken with a sip of water prior to coming to the hospital on the morning of surgery unless specifically advised.

However, there are exceptions. For example, if you take drugs to thin your blood (such as warfarin, aspirin or clopidogrel), drugs for diabetes or herbal remedies, you will need specific instructions.

General advice:-

Aspirin – usually continued up to the day of surgery. If you are not sure, your anaesthetist or surgeon will advise you.

Warfarin – the plan will depend on the reason you have been prescribed warfarin and also the type of surgery you are having. Warfarin may need to be stopped 5 days prior to surgery, stopped and a replacement ‘bridging’ medication given till the day of surgery or continued up to the day of surgery.

Clopidogrel – the plan will depend on the reason you have been prescribed clopidogrel and the time period you have been taking it for and also the type of surgery you are having. This is usually decided in a consultation between the surgeon, anaesthetist and treating cardiologist. If it needs to be stopped this is 7-10 days prior to surgery.

Diabetic Medications

Oral Antihyperglycaemics

  • Metformin – stop 2 days prior to surgery.
  • All other antihyperglycaemics – omit on the day of surgery.

Insulinspecific instructions are required depending on the type and amount of insulin you are taking.


It would be ideal for you to quit smoking but if you cannot do this, reduce the amount you smoke.

The evidence shows that there is less complications if smoking is ceased 6 weeks or more prior to surgery.

If you feel unwell

If you feel unwell when you are due to come into hospital for your operation, the hospital will need to know. Depending on the illness and how urgent the surgery is, your operation may need to be postponed until you are better. Your hospital should give you details of who to contact.