Medications
PPIs (Omeprazole) Before Surgery
If you take a proton pump inhibitor (PPI) such as omeprazole for acid reflux or heartburn, you're probably wondering whether to pause it before your operation. The good news: these are low-concern medicines that are almost always continued.
Quick answer
Why it matters
A proton pump inhibitor lowers how much acid your stomach makes. People take one for acid reflux (GORD), heartburn, indigestion, a healing stomach ulcer, or to protect the stomach lining while on other medicines. Stopping suddenly can let acid symptoms flare back up — sometimes worse than before — which is the last thing you want around the time of an operation.
For anaesthesia, less stomach acid is actually a plus. Under a general anaesthetic your normal reflexes are paused, so the main concern is stomach contents coming up and reaching the lungs. A PPI works with the standard fasting instructions to keep your stomach calmer and less acidic, which is why anaesthetists are comfortable continuing it — and why they sometimes prescribe a dose before surgery to make the stomach environment safer.
Because the benefit carries on into the operation and there's no meaningful bleeding or anaesthetic risk from these tablets, the standard advice is to take your PPI as usual, including on the morning of surgery with a small sip of water unless your team has told you otherwise.
Do not stop without instruction
What to ask your doctor
- Should I take my PPI on the morning of surgery, and with how much water?
- Will the anaesthetist give me anything extra to reduce stomach acid before I go to sleep?
- I also take other tablets — which of those should I continue or pause on the day?
- If my reflux flares up while I'm fasting, what can I safely do or take?
Red flags — call your team
Red flags — call your team
- Severe or new chest pain, or pain spreading to your arm or jaw — this needs urgent assessment, not just antacids
- Vomiting blood, or black, tar-like stools — a sign of bleeding that needs medical attention before surgery
- Difficulty or pain when swallowing, or food feeling stuck — tell your team before your operation
References
- Major anaesthetic and surgical bodies (such as guidance reflected by the Association of Anaesthetists and standard pre-operative medication reviews) list proton pump inhibitors among medicines that are generally continued through the day of surgery, and PPIs are commonly used to reduce gastric acidity before anaesthesia.
- This page is general information. Your own anaesthetic and surgical team's instructions always take precedence over anything written here.
Frequently asked questions
Can I take omeprazole on the morning of my operation?
Yes, in almost all cases. PPIs are usually continued on the day of surgery, taken with a small sip of water as part of your normal medicines. A lower-acid stomach is helpful for safe anaesthesia, so there's rarely a reason to skip it. The only exception is if your own team has given you a different, specific instruction — so confirm your medication plan at your pre-operative assessment.
Does omeprazole interfere with the anaesthetic?
No. Proton pump inhibitors don't interfere with anaesthetic drugs and don't increase bleeding the way some other medicines can. If anything, they help by reducing stomach acid, which is why anaesthetists are happy to continue them and may even give a dose before surgery. They're considered a low-concern medicine around the time of an operation.
Why would the anaesthetist give me a PPI before surgery?
To make your stomach less acidic before you go to sleep. Under general anaesthesia, your protective reflexes are paused, so reducing stomach acid lowers the risk if any stomach contents were to come up. Giving a PPI (or a similar acid-reducing medicine) beforehand is a routine, precautionary step in some anaesthetic plans — a sign of careful preparation, not a problem.
What if I forget to take my PPI on the day of surgery?
Don't worry — it's not an emergency, and missing a single dose is unlikely to cause harm. Let the nursing or anaesthetic team know when you arrive; they can often give you a dose or an equivalent acid-reducing medicine if appropriate. Avoid taking extra tablets to 'catch up' without asking. The team would rather you tell them than try to fix it yourself.