Expert: Patients on GLP-1s Should Consider Dietary Changes, Possible Side Effects During Treatment

In an interview with Pharmacy Times®, Donna Ryan, MD, professor emerita from the Pennington Biomedical Research Center in Baton Rouge, Louisiana, highlights potential side effects and proper safety and nutritional guidelines for patients who are prescribed glucagon-like peptide-1 (GLP-1) receptor agonists for weight management. Ryan explains common occurrences that might occur with GLP-1 treatment, including vomiting and nausea, and the necessary dietary considerations for patients while they are on treatment.

Ryan highlights the role that pharmacists can play in educating patients regarding potential complications and proper treatment protocols for GLP-1s.

Closed captions on this video were auto-generated by artificial intelligence.

Pharmacy Times: What are some factors that patients should be considering when deciding whether to begin using a GLP-1 medication?

Donna Ryan, MD: Well, first of all, I think everybody needs to sit back and take a deep breath. These are not magic pills. They're serious medications, and so you don't really want to take them for cosmetic purposes. Any cosmetic procedure requires a lot, a lot, a lot of safety. How can you justify taking someone who's perfectly healthy and exposing them to health risks just because they want to look skinnier? No, no, no. These medications are not for cosmetic use. That's number one. If you do have a health risk or even health complications of overweight and obesity, these drugs are a serious consideration. But again, safety is the number 1 issue, and so we never prescribe these drugs to people who have a personal or family history of medullary thyroid cancer or multiple endocrine neoplasia type 2, which is a rare genetic disease that predisposes one to this type of cancer. Fortunately, medullary thyroid cancer is rare, but patients who have this should not take these drugs. Sometimes, patients can be allergic to these drugs. They are, after all, peptides—they're proteins. So, you can become allergic. They should wait until we have some small molecules around before trying this. That's also, fortunately, very rare. Otherwise, we have a pretty good idea of what the safety profile of these drugs is, because the class has been around for 20 years.

I would say the most important thing to know, for patients to know, about these drugs is that the chief side effect is going to be nausea and vomiting, and the best way to manage that is to try to prevent it. Number 1: On the day you take your shot and for the few days after that, you should be very careful about what you eat. You need to put less food on your plate—eat only about a half of what you're used to eating—and change the food on that plate. You want to eat foods that aren't very dense and greasy. You want to eat foods that are lighter and that have less fat in them. Also, be sure to drink enough water, because sometimes when people don't eat, they're not getting in enough water. Those sorts of things can help prevent the nausea and vomiting. If the nausea and vomiting are severe, call your doctor. It is possible to get dehydrated because of severe nausea and vomiting. Fortunately, that's pretty rare; but still, if it's happening to you, it's not rare. You want to call your doctor because you don't want to get dehydrated, because that can trigger kidney failure. Yeah. We don't want extreme dehydration, so call your doctor and go get hydrated up in the emergency room or whatever. I think those are the chief things that patients need to worry about.

The way these drugs work is through appetite. They change your relationship with food. You're not interested in the foods that you used to be interested in. You don't have the hunger, and you're also going to get full sooner. Don't just eat because it's on your plate. Listen to your body and stop eating. But also, you need to get in enough calories to make it safe. Sometimes, in some people, the effects of even low doses are very profound, with total absence of appetite. You must take in at least 1000 calories a day. Listen to me: you must consume at least 1000 calories a day. If you don't, you're going to get in trouble. You know, back in the old days, we would do these starvation diets. People would be on 500 calories a day, even less, and they're dangerous because if you're not getting enough high-quality protein, you run the risk of heart arrhythmias or a sudden death. So, you cannot stop eating. You must consume at least 1000 calories a day. If you have to, go to a high-protein shake, like Boost or one of the other supplements, but be sure to get in enough calories. You're going to lose plenty of weight on 1000 calories a day. Start low, start with the lowest dose, and escalate slowly. That's mostly to avoid those side effects. Don't lose too much weight. All the drugs have different doses that are available, and your doctor is going to help you find the lowest, most effective dose for you. You don't have to push that dose up if you don't need to. So those are the chief things that patients need to know around safety.

Pharmacy Times: What are some lifestyle changes patients should be making to their routine, not only to prevent adverse events but also to help maximize the benefits of their GLP-1 medications for the short term and long term?

Ryan: I'm so glad you asked that question, because these medications are a window of opportunity to a healthier lifestyle. You will get the benefits of weight loss itself, but if you can change your diet to a higher quality diet, and if you can change your lifestyle to include more physical activity, you will get health benefits from that. Yeah. So, we want to move to a healthier diet, a higher quality diet. We know the Mediterranean diet has health benefits. We know that from a randomized clinical trial, a gold standard clinical trial. We know that fitness is a big driver of longevity and better health. This is a window of opportunity. Don't just use these drugs to eat less; use them to have a higher quality diet and a healthier, happier lifestyle.