Rybelsus (semaglutide) is an oral GLP-1 receptor agonist used to manage type 2 diabetes, but its use around surgery requires careful consideration. The medication slows gastric emptying, which may theoretically increase aspiration risk during anaesthesia. Current UK practice does not routinely recommend stopping Rybelsus before all procedures; instead, decisions are individualised based on procedure type, patient risk factors, and local protocols. Your anaesthetic and diabetes teams will assess your specific circumstances and provide tailored guidance. This article explains when Rybelsus might be withheld, how to manage blood glucose during any pause, and when to safely restart after your operation.

Why Rybelsus May Need to Be Considered Before Surgery

Rybelsus (semaglutide) is an oral glucagon-like peptide-1 (GLP-1) receptor agonist used to improve blood glucose control in adults with type 2 diabetes mellitus. While this medication offers benefits for blood sugar management, it requires careful consideration in the perioperative period. The primary concern relates to delayed gastric emptying, a known pharmacological effect of GLP-1 receptor agonists.

GLP-1 receptor agonists work partly by slowing the rate at which food leaves the stomach, which helps control post-meal blood glucose levels. However, this mechanism could potentially increase the risk of pulmonary aspiration during anaesthesia. When gastric emptying is delayed, stomach contents may remain present even after standard fasting periods, creating a risk that stomach acid or food particles could enter the lungs during intubation or whilst under general anaesthesia.

Anaesthetic and surgical teams need to know if you are taking Rybelsus so they can make appropriate decisions about perioperative management. For patients with significant risk factors—such as those experiencing gastrointestinal side effects, those in the dose-escalation phase, or those with known gastroparesis—additional precautions may be considered. These might include rapid sequence induction or point-of-care gastric ultrasound to assess gastric contents and minimise aspiration risk.

Your anaesthetist will assess your individual risk and determine the most appropriate approach for your procedure, which may include continuing or temporarily pausing your medication depending on your specific circumstances.

How Long to Stop Rybelsus Before a Surgical Procedure

The approach to Rybelsus before surgery depends on the type of procedure you're having, your individual risk factors, and your local hospital's policy. Current UK practice generally does not recommend routine stopping of GLP-1 receptor agonists for all patients before surgery.

For most elective (planned) procedures, you may be advised to continue Rybelsus as normal, with your anaesthetist taking appropriate precautions to manage any potential increased aspiration risk. However, some patients may be advised to withhold Rybelsus temporarily, particularly if they:

• Are experiencing significant gastrointestinal side effects

• Are in the dose-escalation phase of treatment

• Have known gastroparesis or delayed gastric emptying

• Are undergoing procedures with higher aspiration risk

If your clinical team does recommend withholding Rybelsus, they will provide specific instructions about when to stop. This might range from omitting just the dose on the day of surgery to stopping for a longer period, depending on your individual circumstances and local guidelines.

Never stop Rybelsus without medical guidance. Your healthcare team will provide specific instructions tailored to your situation and will arrange alternative diabetes management strategies during any period when Rybelsus is withheld. For emergency surgery, your anaesthetist will take appropriate precautions based on when you last took your medication.

It is essential to discuss your diabetes medications with both your diabetes team or GP and your surgical team well in advance of your operation to ensure a coordinated approach to your care.

Potential Risks During Surgery

If you continue taking Rybelsus up to the time of surgery, your anaesthetic team will consider certain potential risks during the perioperative period. The main consideration is the possibility of delayed gastric emptying, which could theoretically increase the risk of aspiration during anaesthesia. There have been case reports where patients taking GLP-1 receptor agonists had gastric residue despite following standard fasting protocols, though the overall frequency of this complication is not well established.

If aspiration occurs, it can lead to aspiration pneumonitis (inflammation of lung tissue caused by acidic stomach contents) or aspiration pneumonia if particulate matter enters the lungs. Your anaesthetist will assess your individual risk and may implement additional precautions such as modified airway management techniques if they have concerns.

Regarding blood glucose management, Rybelsus itself has a low risk of causing hypoglycaemia when used alone. However, if you take Rybelsus alongside insulin or sulfonylureas (such as gliclazide), the risk of low blood glucose during the fasting period before surgery may be increased. The stress response to surgery typically raises blood glucose levels, making perioperative diabetes management a careful balance.

For most medications, Rybelsus does not significantly affect their absorption. However, if you take medications with a narrow therapeutic index (where precise blood levels are critical), your doctor may monitor these more carefully around the time of surgery.

Your anaesthetic team will take all these factors into account when planning your care, ensuring the safest approach for your procedure while maintaining good blood glucose control.

When to Restart Rybelsus After Your Operation

Restarting Rybelsus after surgery requires careful consideration of several factors to ensure safe resumption whilst maintaining good blood glucose control. The timing depends primarily on your recovery from anaesthesia, your ability to tolerate oral intake, and the type of surgery you have undergone.

For most patients, Rybelsus can typically be restarted once you are:

• Fully recovered from anaesthesia and alert

• Able to eat and drink normally without nausea or vomiting

• Tolerating solid food comfortably

• No longer experiencing significant postoperative complications

Following major abdominal surgery, gastrointestinal procedures, or operations with complications, a longer delay may be necessary. Your surgical team will advise when normal bowel function has returned and when it is safe to resume oral medications.

It is important to remember that Rybelsus requires specific administration conditions for optimal absorption. It should be taken:

• First thing in the morning

• With no more than 120 ml of water

• On an empty stomach

• With no food, drink, or other oral medications for at least 30 minutes afterwards

Ensure you can comply with these requirements before restarting. If you've been off Rybelsus for an extended period, your doctor may recommend restarting at a lower dose initially to minimise gastrointestinal side effects, then gradually increasing back to your usual dose.

Your diabetes team or GP should provide clear written instructions about when to restart Rybelsus as part of your discharge planning. Always confirm the restart plan with your healthcare provider rather than making this decision independently.

Managing Blood Sugar While Rybelsus Is Paused

Maintaining adequate blood glucose control during any period when Rybelsus is withheld is essential to optimise surgical outcomes and promote healing. Your diabetes healthcare team will develop an individualised management plan to bridge this period safely.

For many patients with type 2 diabetes, continuing other diabetes medications may provide sufficient control. If you take metformin, this is generally continued until the day of surgery for most procedures, though it may be temporarily stopped if you have reduced kidney function, are having a procedure using contrast dye, or are undergoing major surgery with restricted eating and drinking afterwards.

SGLT2 inhibitors (medicines ending in '-flozin') are typically stopped 3 days before surgery (4 days for ertugliflozin) due to the risk of diabetic ketoacidosis. Your doctor may advise monitoring your ketone levels if you've recently been taking these medications. Sulfonylureas (such as gliclazide) may be adjusted or temporarily stopped to reduce hypoglycaemia risk during fasting periods.

Some patients may require temporary insulin therapy whilst Rybelsus is paused, particularly for major surgery or if your blood glucose control is suboptimal. For inpatient procedures, this might involve a variable rate intravenous insulin infusion to maintain your blood glucose between 6-10 mmol/L.

Self-monitoring of blood glucose becomes particularly important during this period. You should check your blood glucose levels more frequently than usual—typically before meals and before bed, or as directed by your healthcare team. Keep a record of these readings and report any values consistently above 15 mmol/L or below 4 mmol/L to your diabetes nurse or GP.

Maintain good hydration and follow any dietary advice provided. If you experience symptoms of high blood glucose (increased thirst, frequent urination, fatigue) or low blood glucose (trembling, sweating, confusion), contact your healthcare provider promptly.

If you experience any suspected side effects from your diabetes medications, you can report these through the Yellow Card Scheme at yellowcard.mhra.gov.uk.

Frequently Asked Questions