By: Dr. Vijay Subramaniam, DO
Obesity has been an ongoing issue in the United States for years. However, it is not just fast food, supersized meals, buffets, or overconsumption that has led to this rise in obesity, but genetic, economic, environmental, and cultural factors. The National Institutes of Health (NIH) reports that from 2017–2018, nearly 1 in 3 adults (30.7%) were classified as overweight and more than 2 in 5 adults (42.4%) as obese. Whether it's you, a loved one, friends, or colleagues, we all know someone who has been impacted by obesity. Now, what do I mean by obesity? Obesity refers to a person whose weight is higher than their normal weight for a given height. For adults, it is measured by looking at your body mass index (BMI), which is a ratio of your weight to your height. A BMI of greater than 30 kg/m2 is considered obese. In children and teenagers, a percentile range is used, and weight relative to height is considered, with obesity being greater than the 95th percentile.
Many interventions, such as daily exercise, reduced screen time, and healthier diets, have helped to combat obesity. For some, reaching a healthier weight can be a struggle, despite their best efforts. This is where new drugs called GLP-1 agonists or activators come into play. You have probably seen these drugs, like Ozempic, Wegovy, Trulicity, and Saxenda, mentioned on the news or in commercials. Originally used to treat type 2 diabetes mellitus, these drugs have now become popular for weight loss. Recently, a new drug called tirzepatide, better known by the brand names Mounjaro or Zepbound, has hit the market.
Now you may be wondering how tirzepatide (Mounjaro) works. Just like Ozempic, this drug works to activate a protein called GLP-1, which is responsible for signaling that we are full while also helping the body release insulin. Insulin is a hormone that is released from the pancreas and helps us shuttle sugar, protein, and fat into cells. Insulin is used to treat both type 1 and type 2 diabetes. In addition, this drug also works on GIP, or gastric inhibitory peptide, helping to further reduce high blood sugar, called hyperglycemia, and suppress appetite.
How much tirzepatide (Mounjaro) should you use? Typically, your doctor will start you at a dose of 2.5 mg once weekly and after approximately 4 weeks, your dose may be increased to 5 mg. Based on your response and side effects, your doctor will consider increasing every 4 weeks up to the maximum dose of 15 mg or keeping you at a lower dose. It takes at least 20 weeks to get to the highest dose.
How is tirzepatide (Mounjaro) administered? Tirzepatide is administered once every week by injection or subcutaneously. The frequency will vary based on the GLP-1 agonist medication you are prescribed, from daily to weekly injections. Mounjaro can use a small, 32-gauge, or approximately 4-mm needle.
How soon does tirzepatide (Mounjaro) start working? The medication starts working within hours of your first injection and takes about 4-6 months to see the full effects. If weight loss is minimal after 6 months, your doctor may switch you to another medication in the same GLP-1 class, such as Wegovey or Ozempic. However, research from the drug manufacturer has shown that even the majority of slow responders to the medication went on to lose at least 15% of their body weight by week 72.
What happens if I can’t find my medication or forget to take it? If a dose is missed for any reason, try to administer it within 4 days of the scheduled date. Otherwise, you should wait until next week to restart tirzepatide on your regular schedule.
What about “Ozempic Face"? This is a side effect of all GLP1 drugs, including Mounjaro, and has to do with rapid weight loss caused by the medication. Some signs of “Ozempic face” include changes in lip, cheek, and chin structures, sunken eyes, and wrinkles. It can be minimized by slowly increasing the dose of medication so that weight loss occurs more gradually. Significant facial changes may require discontinuing the medication or plastic surgery.
What other side effects should I expect? The most common side effects are nausea, vomiting, constipation, and diarrhea. Some patients have also reported rashes and bruising at the injection site. Rarely, patients may experience pancreatitis or inflammation of the pancreas due to overstimulation of this gland by GLP-1 and GIP, inflammation or infection of the gallbladder called cholecysitis, gall stones, acute kidney injury due to severe dehydration, and at higher doses of 10–15 mg low blood sugar called hypoglycemia.
Signs your blood sugar may be low include fatigue, sweating, tremors, shivering, and seizures. Notify your doctor if you experience severe nausea or vomiting, are unable to pass gas or have a bowel movement, have severe belly pain, or notice your skin turning yellow.
To minimize the gastrointestinal side effects, try to eat smaller meals, avoid activity right after eating, keep well hydrated, eat plenty of fiber, avoid any strong smells, and eat a mint or ginger-based food about half an hour after injecting the medication.
In addition to a healthier diet and exercise, drugs like Mounjaro can make a significant difference in the lives of many people who suffer from obesity. Though these GLP1-class drugs seem to be well tolerated by the majority of patients, long-term studies are still needed. If you are interested in starting Mounjaro, set up an appointment with your primary care physician or weight loss specialist.
References
GLP-1 diabetes and weight-loss drug side effects: "Ozempic face" https://www.health.harvard.edu/staying-healthy/glp-1-diabetes-and-weight-loss-drug-side-effects-ozempic-face-and-more
Ozempic, Trulicity, and More: 10 GLP-1 Agonist Drugs and How to Navigate Your Options https://www.goodrx.com/classes/glp-1-agonists/glp-1-drugs-comparison
Overweight & Obesity Statistics https://www.niddk.nih.gov/health-information/health-statistics/overweight-obesity
Tirzepatide https://www.ncbi.nlm.nih.gov/books/NBK585056/
A systematic review of the safety of tirzepatide-a new dual GLP1 and GIP agonist - is its safety profile acceptable? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10084319/
If at First Tirzepatide Doesn't Succeed, Keep Trying https://www.medscape.com/viewarticle/if-first-tirzepatide-doesnt-succeed-keep-trying-2024a100090d?ecd=mkm_ret_240530_mscpmrk_endo_top_etid6558437&uac=346609HX&impID=6558437
Everything You Need to Know About Mounjaro https://vakares.com/tag/mounjaro/
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