What the heck is a GLP?
By Ann Lima, MD
It is likely you have heard about a groundbreaking class of medications for diabetes and weight loss. What you may not know is that these medications also have a role in treatment of other disease processes such as heart failure, cardiovascular disease, chronic kidney disease, metabolic associated fatty liver disease, and obstructive sleep apnea.
The class of medications is called glucagon-like peptide-1 (GLP-1) receptor agonists (a mouthful for sure!) and the most widely used is called semaglutide. They work on different messaging systems in our body to control blood sugar and lose weight. One of these messages goes to the brain to make us less hungry. Another message goes to the pancreas to send out insulin, which helps glucose (aka blood sugar) get taken up into cells to be used for energy. It also prevents the liver from making more glucose. It slows down the food you eat from leaving your stomach and making you feel full longer.
There are also medications that use the GLP-1 effect and additionally target the GIP (glucose-dependent insulinotropic polypeptide), like tirzepatide, which is generally more effective than semaglutide due to its dual action. This medication doubles down on insulin and makes it work better and should not make glucose go too low unless combined with other medications. This medication also helps your bones, as opposed to GLP-1 medications.
Although these can be life-changing medications for many, there are also significant side effects that need to be considered. The most common is nausea, and can also lead to vomiting, diarrhea and constipation. These effects, along with decreased water intake, can lead to dehydration and kidney damage if not managed appropriately. If you already have slow food transit, it can get worse when taking these medications. Rapid weight loss and nutritional deficiencies can occur which can lead to hair loss and changes in body appearance especially in the fat tissue. If you take these medications with other diabetes medications like insulin or glipizide, glimepiride or glyburide, it can make you have low blood sugar. It can decrease the effectiveness of birth control pills due to delayed absorption.
To manage these side effects, it is important to discuss them with your provider, start at the lowest dose of medication and escalate slowly, usually slower than the label suggests and step back to a lower dose if needed. Eat small, frequent meals, stop eating when full, and avoid fasting. Limit fatty, fried, spicy, high sugar foods, alcohol and carbonated beverages. Make sure to increase fluid intake to at least 2-3 liters (64 to 96 ounces) of water a day, eat fiber-rich foods and consider psyllium supplements. Make sure protein is emphasized in your diet to preserve lean muscle mass.
Cost, coverage and availability vary for all options. Innovation continues and we will see more choices in the future, both in pill and injectable form, and with additional actions. Please consult your healthcare provider to help you make the best decision for your situation.