GLP-1 RAs bring surgical risks

Delayed gastric emptying can increase the risk of dangerous complications during endoscopy or gastric surgery.

---

Taking glucagon-like peptide-1 receptor agonists in the month before endoscopy can delay gastric emptying and cause dangerous complications during anaesthesia, say researchers. 

And experts warn the highly sought-after injectables used for weight loss should stop taking the drugs at least a month before endoscopy or bariatric surgery. 

Writing in the MJA, Australian researchers reported cases of delayed gastric emptying in patients who took GLP-1 RAs a few weeks before gastric surgery. 

One study found that patients who took semaglutide in the month before endoscopy had five times the rate of retained gastric contents compared to patients who didn’t use the drug, they said. 

“In patients treated with GLP‐1 RAs and additional medications that delay gastric emptying, or in patients with gastrointestinal symptoms, the risk of aspiration is likely higher,” the authors wrote.  

“Given the long half‐life of the weekly preparations, it is likely that withholding semaglutide or dulaglutide for one week will be insufficient to prevent the effects on gastric emptying. A longer cessation time, combined with prolonged fasting, may be required.”  

Longer fasting times may be necessary in patients taking the medications, they wrote. In the absence of evidence, a 24‐hour clear fluid regimen could be considered regardless of the procedure or anaesthetic technique planned, especially if the GLP-1 RAs has recently been commenced, they added.  

The authors said that despite the increase in GLP-1 RA use outside of type 2 diabetes, “there has not been a clear distinction in how to approach the peri‐operative period in patients without diabetes receiving GLP‐1 RAs”. 

They said one study of more than 400 oesophagogastroduodenoscopy patients found that 24% of patients retained solid gastric contents or more than 0.8 mL/kg of retained fluid content if they were exposed to semaglutide in the 30 days before the procedure, compared with 5% of patients who were not exposed. 

“The presence of gastrointestinal symptoms in the 24 hours before the procedure was associated with retained gastric contents,” they said.  
 
“Interestingly, the mean time since last dose of semaglutide was 10 days, and one patient in the semaglutide group developed pulmonary aspiration.”  

Another endoscopy patient experienced pulmonary aspiration associated with retained gastric contents after starting semaglutide two months earlier, they said. 

Upper gastrointestinal surgeon and senior research fellow at Monash University, Dr Paul Burton, said he saw many patients who had taken weight loss drugs such as GLP1s before bariatric surgery. 

“There are significant risks if people are on those medications and they’re coming for surgical procedures or a gastroscopy, because the stomach doesn’t empty, so they’re at risk of food coming back and aspirating and having a serious complication. That is a problem for us at the moment,” he said. 

“That’s because the drugs are new, and they’re being widely used, and that’s something that we’re becoming aware of now. It’s a significant issue.”  

Dr Burton, who performs bariatric surgery in private practice, said there were significant additional surgical risks when performing surgery on the stomach or oesophagus – such as bariatric surgery – due to the presence of food content rather than an empty stomach.  

The stomach needed to be empty for surgery to be performed because it involves cutting through the stomach, he said. 

“You can’t do bariatric surgery on someone who’s taking one of these medications. They’ve got to be off for a month or so,” said Dr Burton.  

He said the paper highlighted that it was unclear what the appropriate duration was to stop weight loss medications before surgery or other procedures. 

Dr Burton said most patients would have tried weight loss medication before seeking bariatric surgery. 

“It’s just common sense to try everything you can before you take the step and have surgery,” he said. 

“That’s certainly a requirement before we undertake surgery. Somebody has to have made significant endeavours to lose weight on their own and they’ve got to be serious about it.  

“I’ve never seen anyone who the first thing they do to control their weight is to come in and see a surgeon.  

“Invariably, people have been trying for years and having some success, then regaining their weight. But if something new is available, and it’s clearly effective, then it’s logical that a lot of people are going to try it. 

“There needs to be caution with regards to who prescribes, because it does have side effects, and it’s a complex medication.” 

The researchers said there had been few large studies investigating the effects of GLP-1 RAs on gastric emptying and that the effects of the drugs on gastric emptying differed between short‐ and long‐acting formulations. Some conditions and other medications could also delay gastric emptying. 

“Diabetes itself is associated with delayed gastric emptying,” they wrote. 

“Commonly co‐prescribed medications that affect gastric emptying peri‐operatively include opioids and proton pump inhibitors.  

“We propose that if patients are treated with additional drugs that slow gastric emptying, further consideration of this risk should be accounted for when deciding fasting time and airway support.” 

Last year researchers reported two cases of patients who took semaglutide and liraglutide before gastroscopies. Their procedures had to be abandoned because their stomachs were full of solid food despite having fasted for 13 and 10 hours respectively. 

“It is now recommended that GLP-1 RA be withheld for one dose prior to gastroscopy,” they wrote in the American Journal of Medicine.  

“A longer period of cessation, longer fasting time, or both, may be required, particularly if the GLP-1 RA was commenced close to when the endoscopy is performed.”  

MJA 2024, online 15 January