Extended Fasting Required Before Procedure for GLP-1 Analog Users

You must have heard about Ozempic, Tirzepatide, or other weight loss medications which are causing quite a stir in public.

These drugs are actually a part of glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs) class of medicines.

One of their mechanisms of action includes delaying stomach emptying, which can affect how doctors manage patients taking these medications before certain procedures.

But is the gastric emptying really delayed, and if yes, to what extent? To answer this question, a recent study has analyzed this and found out how this might influence periprocedural care.

Divergent Practices and Limited Evidence

In this study, the authors have pointed out that there are different opinions on how to handle GLP-1 RAs around the time of medical procedures.

This is because professionals have their own concerns about any problems during sedation.

A common one is inhaling stomach contents, called aspiration, which is a serious danger during anesthesia or sedation. If the stomach is not empty, food or fluids might come back up and go into the lungs.

Doctors usually suggest fasting before procedures to keep the stomach empty and lower the risk of aspiration.

But for people taking GLP-1 RAs, the problem is that these drugs might slow down how fast the stomach empties [ref].

This could increase the chance of aspiration during sedation. Some doctors think the delay caused by GLP-1 RAs might be minimal and not really affect the risk much, but some disagree.

This confusion happens because there is not enough good data on exactly how GLP-1 RAs affect stomach emptying.

Methodology:

To fill this knowledge gap, the researchers did a systematic review and meta-analysis.

This is different from traditional research as this method means looking for related studies in an organized way, choosing the best ones using certain rules, and then mixing their data to make stronger conclusions.

The study looked at research that measured the effects of GLP-1 RAs on gastric emptying.

They looked for studies that used known methods like gastric emptying scintigraphy (GES) or the acetaminophen absorption test (AAT) to see how fast the stomach empties its food.

Key Findings: Quantifying the Delay

The analysis included fifteen studies that met the inclusion criteria. Five of these studies used GES, which is a method that uses a radioactive marker to follow how food or liquids move through the stomach.

The data showed that there was a noticeable delay in how fast the stomach emptied in patients taking GLP-1 RAs compared to those taking a placebo.

On average, the time for half of the stomach’s contents to empty (T1/2) was about 36 minutes longer with GLP-1 RAs.

However, the results were more detailed when the ten studies that used the AAT were checked.

This test checks how long it takes for the painkiller acetaminophen to be absorbed from the stomach into the blood.

The AAT is different from GES as it mainly shows how liquids empty from the stomach.

Furthermore, the AAT results showed no big changes in stomach emptying between patients taking GLP-1 RAs and those taking a placebo.

Factors Not Affecting Gastric Emptying.

The researchers wanted to see if specific features of these drugs or the way they are injected affect how much they slow down the stomach emptying.

For this reason, they used a special statistical method called meta-regression analysis, which looks at how differences in these features are related to the delay in stomach emptying.

They examined things like the type of GLP-1 RA medicine (such as liraglutide or exenatide), whether it works quickly or slowly, and how long the treatment lasts.

None of these features were found to change how much the GLP-1 RA medicines slowed down stomach emptying.

Uses for Periprocedural Management

The key point from the study is that GLP-1 RAs slow down stomach emptying by about 36 minutes, as shown by GES, but this delay is quite small.

The mentioned delay is more noticeable for liquids, which is important for fasting rules before procedures.

Normal fasting times before procedures mean no food or clear liquids for several hours, which is much longer than the delay caused by GLP-1 RAs.

Researchers think that current fasting rules before procedures might be too strict for people taking GLP-1 RAs.

They suggest that for low-risk procedures, it might be better to tailor fasting rules based on the specific drug, time since the last dose, and type of fluids.

Summarising the Findings:

Source: the study was published in the American Journal of Gastroenterology.