All you need to know about the FDA-approved medication for obesity

The medication Zepbound was recently approved by the US Food and Drug Administration to address chronic obesity. Created by Eli Lilly, this injectable drug contains tirzepatide as its active ingredient, which was previously approved in May 2022 to treat type 2 diabetes known as Mounjaro.

Tirzepatide now joins semaglutide, another medication initially developed for diabetes treatment called Ozempic. However, semaglutide has also received approval to treat obesity and is now known as Wegovy. Extensive studies on both medications have demonstrated their strong efficacy in managing both diabetes and obesity.

What sets Zepbound apart from Wegovy? How do they operate and what is their effectiveness? What duration of usage is recommended? What are the potential adverse effects? Should individuals explore cheaper alternatives from online pharmacies? And who should consider these medications and who should avoid them?

In order to gain further insight into these medications, I engaged in a conversation with Dr. Leana Wen, a CNN wellness medical expert. Dr. Wen is an emergency physician and a professor of health policy and management at the George Washington University Milken Institute School of Public Health. She has previously held the position of health commissioner in Baltimore.

CNN: What are the differences between Zepbound and Wegovy? What is their mode of action?

Dr. Leana Wen: Both Zepbound and Wegovy are injectable medications meant for weekly usage. Initially approved to address type 2 diabetes, clinical trials have also demonstrated their effectiveness in inducing substantial weight loss. While Wegovy is presently available in the market, Zepbound has recently gained FDA approval and is anticipated to be released later this year.

Both drugs belong to the GLP-1 agonist class, imitating the digestive hormone GLP-1 released by the intestines after eating. GLP-1 promotes insulin production, lowering blood glucose levels, while also decreasing appetite and inducing a feeling of satiety. Along with mimicking GLP-1, tirzepatide also mimics GIP, another gut hormone believed to have a comparable impact on the body.

CNN:  How well do these drugs work to reduce weight?

The injectable medication Zepbound, manufactured by Eli Lilly, was approved by the FDA on November 8 to treat chronic obesity.

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Wen: The effectiveness of these medications is impressive. A study published in The New England Journal of Medicine in March 2021 demonstrated that individuals taking semaglutide lost an average of 14.9% of their body weight over the course of a year, compared to just 2.4% in the placebo group. Similarly, a study published in JAMA Network Open in September 2022 revealed that, after six months, the average weight loss for participants was approximately 27 pounds (12.3 kilograms).

Tirzepatide also exhibits remarkable efficacy. A seminal study published in The New England Journal of Medicine in July 2022 found that individuals taking a lower dose of tirzepatide experienced an average weight reduction of 16%, or 35.5 pounds (16 kilograms), over the course of a year. Those taking a higher dose achieved a 21.4% reduction in body weight, equivalent to 49 pounds (22 kilograms). These reductions far exceed those observed in individuals who received a placebo, who achieved an average weight reduction of merely 2.4% or 5.3 pounds (2.4 kilograms).

CNN asked if tirzepatide is more effective than semaglutide. Wen responded by saying that the studies conducted did not directly compare the two medications. Therefore, it is not possible to claim that one is superior to the other at this point. Like any medication, the effectiveness may vary among individuals.

CNN: What is the recommended duration for taking these medications?

Wen: Currently, it is recommended to take tirzepatide and semaglutide for the rest of one's life, as discontinuing them may result in a reversal of a significant portion of the weight loss achieved.

CNN: Are there potential side effects associated with the use of GLP-1 medications?

Yes, there is. Numerous individuals encounter gastrointestinal problems such as nausea, diarrhea, vomiting, and constipation. In rare instances, the medications have been linked to pancreas, gallbladder, and stomach complications. Since tirzepatide and semaglutide are relatively novel treatments, the long-term effects remain unknown.

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CNN: Should people consider more affordable versions of drugs that some internet pharmacies sell?

The safest option is to purchase medications directly from the manufacturers - Eli Lilly for tirzepatide and Novo Nordisk for semaglutide. However, this requires a valid prescription from a healthcare provider and a visit to the pharmacy to obtain the medications. It is worth noting that the specific medications needed for obesity treatment are Zepbound and Wegovy.

In addition, physicians have the ability to prescribe Mounjaro and Ozempic "off-label." Although these drugs are officially approved to treat diabetes, they can also be prescribed to individuals without diabetes who require them for weight loss, as the active ingredients (tirzepatide and semaglutide) remain the same.

Pharmacies have the ability to create their own versions of certain drugs through a process known as compounding. Skilled pharmacists are able to reformulate medications and sell them.

Compounding is permitted by the FDA in specific situations, such as during drug shortages like those being experienced with semaglutide and tirzepatide. However, it's important to note that unlike the medications produced by manufacturers, compounded drugs are not subject to FDA inspections to ensure their quality, safety, and efficacy. The FDA emphasizes that compounded medications carry a higher level of risk compared to those directly manufactured by the drug companies.

Additionally, it is important to consider the issue of unauthorized online pharmacies engaging in the sale of medications. It is necessary to steer clear of these illegitimate establishments. The FDA provides a useful guide on identifying potential illegal pharmacies that distribute hazardous medicines.

CNN: Who should consider using these drugs and who should refrain?

Wen: Obesity is a chronic medical condition. It is important for individuals to consult with their health care provider and consider taking medication if they have this condition, rather than solely focusing on appearance or trying to lose a few pounds.

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Patients who have a body mass index (BMI) of 27 or higher are eligible for treatment with Wegovy, while Zepbound is approved for those with a BMI of 30 or above. These medications are intended to be used in conjunction with lifestyle changes, comprising increased physical activity and a carefully controlled diet.

It is generally positive that new tools are now available for patients suffering from obesity, as this condition poses increased risks of heart disease, diabetes, various types of cancer, and premature mortality. However, it is important to note that like most medications, these drugs carry potential side effects and risks. Therefore, individuals should carefully consider the potential benefits and drawbacks, as well as communicate with their healthcare professionals about possible alternatives.

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