GI Side Effects, Anesthesia Risks With GLP-1 Agonists

This transcript has been edited for clarity.

Hello. I'm Dr David Johnson, professor of medicine and chief of gastroenterology in Eastern Virginia Medical School in Norfolk, Virginia.

Recent national media attention has focused on the gastrointestinal (GI) side effects of glucagon-like peptide-1 (GLP-1) receptor agonists. These drugs are used to treat type 2 diabetes and weight loss. The GI side effects include nausea, vomiting, and gastroparesis-like symptoms.

I wanted to emphasize two key points especially important to clinicians providing this class of therapy.

One: Clinicians need to be increasingly aware of the potential GI side effects and inform their patients when they start to prescribe these medications.

And two: The American Society of Anesthesiologists (ASA) has recently released consensus-based recommendations for preoperative assessment and management of adults and children undergoing surgery who are taking these medications. The recommendations also apply to endoscopic procedures whereby anesthesia will be delivered.

Gastric Impact of GLP-1 Agonists

What are these GLP-1 agonists? The drugs for weight loss include liraglutide (Saxenda and Victoza) and semaglutide (Ozempic, Wegovy, Rybelsus, among others). The type 2 diabetes medications include semaglutide, dulaglutide (Trulicity), and exenatide (Byetta, Bydureon BCise), among others. They can be taken daily or by injection once a week.

The GLP-1 agonist drug class works at the GI level to increase insulin secretion and decrease glucagon release, both of which mediate glycemic control, particularly postprandially. The drugs slow the gastric motility through decreased peristalsis and increased tonic contractility of the pylorus, essentially causing a delay in gastric emptying.

Dr Michael Camilleri and his colleagues at the Mayo Clinic, in Rochester, Minnesota, conducted a small randomized, placebo-controlled double-blind study of the GLP-1 agonist liraglutide to investigate the mechanism of weight loss in patients who were overweight. They showed that there was a diminution in gastric emptying over 16 weeks in patients taking liraglutide. They found evidence of tachyphylaxis, but the rate of gastric emptying of solids remained slow compared with placebo, even at 16 weeks.

Despite the observed waning of the gastric impact, we just don't know how long significant side effects persist when patients stop the drug for good. There are some reports of patients with protracted symptoms a year or more after they've stopped their GLP-1 agonist medications.

Guidance for Preoperative Management

These drugs would commonly be reviewed before patients go through procedures, and we need to be better aware as we start to see these patients for endoscopy.

The ASA recommendations address the potential consequences of delayed gastric emptying and provide guidance for preoperative management of these drugs to prevent regurgitation and pulmonary aspiration of gastric contents.

In patients on daily dosing, the ASA recommends holding these agents the day prior to the procedure.

For patients on weekly dosing, the recommendations suggest withholding the dose a week before the procedure. Importantly, this should be in consultation with their diabetologist, just to assess any need for a bridging therapy to avoid hypoglycemia.

On the day of the procedure, if GI symptoms, such as severe nausea, vomiting, retching, abdominal pain, and bloating, are present, clinicians should consider delaying the elective procedure and discuss the risks of the potential risks for aspiration.

If the patient has no symptoms and the GLP-1 agonist has been withheld as advised, then you should proceed as usual.

But if the patient has no symptoms and has not held their GLP-1 agonist, you should proceed with what the anesthesiologists call the "full stomach" precaution, which considers patients at potentially high risk for aspiration. There's a way of checking for that. Some centers can do a quick ultrasound on the stomach and see if there's food, debris, or liquid, and if that is not the case, they could proceed with no delay. But if there is no way to check gastric contents, then you should manage accordingly, which may require intubation or postponing an elective procedure for another day.

These are new and changing issues. In our world as gastroenterologists, we should be considering — very strongly — mitigating strategies to protect the patients on this wonderful class of therapy. Sometimes these drugs can have significant side effects that we need to at least be aware of. Nothing is perfect, but let us be better informed.

I'm Dr David Johnson. Thanks for listening.

David A. Johnson, MD, a regular contributor to Medscape, is professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia, and a past president of the American College of Gastroenterology. His primary focus is the clinical practice of gastroenterology. He has published extensively in the internal medicine/gastroenterology literature, with principal research interests in esophageal and colon disease, and more recently in sleep and microbiome effects on gastrointestinal health and disease.

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