Obesity is the most common chronic disease in the United States, with over 42% of adults being affected. Given the numerous health risks of this lifelong progressive disease, treatment should be initiated upon diagnosis. Comprehensive, evidence-based treatment modalities include nutrition, physical activity, behavioral modification, anti-obesity medications (AOMs), and bariatric surgery.

As more clinicians recognize that obesity is a serious chronic disease, they are increasingly prescribing AOMs. As media coverage of the newer agents has increased, more people living with obesity are asking their clinicians to prescribe them.

What Are AOMs?

FDA-approved AOMs are safe, evidence-based therapies that target specific physiology to improve the disease and are most effective when they are used as part of a comprehensive treatment plan. They work primarily by regulating hormones in the brain, digestive system, and adipose tissue to suppress appetite and cravings and promote satiety. Each medication has its own specific mechanism of action.

Why Are AOMs Prescribed? 

• To facilitate weight reduction to improve obesity-related complications, such as type 2 diabetes mellitus, obstructive sleep apnea, and hypertension, as well as to prevent those complications from developing.
• To improve adherence to nutrition plans.
• To counter the effects of metabolic adaptation and prevent weight regain. After weight reduction, the body metabolically adapts, often causing an increase in hunger hormones and a decrease in satiety hormones and resting metabolic rate, all of which can contribute to weight regain.

When Should AOMs Be Initiated?

AOMs can be prescribed at any point in treatment, but shared decision making should be used to determine when to initiate a medication. Starting an AOM at the beginning of treatment may make it easier for patients to stay on their nutrition plan and engage in treatment. For those with obesity-related conditions that significant impair health and quality of life, greater weight reduction early on can yield more immediate improvement. Another option is to encourage the patient to implement lifestyle therapies, such as nutrition plans and physical activity, and monitor their response to those changes before considering an AOM. This strategy helps the clinician identify the patient’s specific challenges, such as hunger, cravings, or a lack of satiety, and then choose a medication that targets those challenges.

AOMs may also be started when patients reach a weight plateau. Given the effects of metabolic adaptation, AOMs can counter the increase in hunger hormones and the decrease in satiety hormones, making it easier for patients to manage eating, prevent weight regain, and induce further weight reduction. Clinicians may need to increase the dose, add another medication, or both, when metabolic adaptation occurs. 

What Are the Most Commonly Prescribed AOMs? 

What Factors Affect AOM Choice?

Medication choice is usually based on the mechanism of action, cost and insurance coverage, and the patients’ preferences on delivery method, frequency of dosing, and willingness to tolerate side effects. Orlistat, for example, is infrequently prescribed because of its potential side effects, which include oily stool, anal leaking, and bowel urgency. Semaglutide 2.4 mg is often the first choice because it may induce the most significant weight reduction, however, lack of insurance coverage and periodic shortages limit its use. Phentermine is the most commonly prescribed AOM because of its low cost. More AOMs are in the pipeline that may induce equivalent or greater weight reduction compared with current medications.

What Are the Benefits of AOMs?

• Reduce obesity-related health risks by inducing weight loss.
• Help reduce food consumption and stay on a nutrition plan.
• Decrease cravings for highly processed food, thereby improving nutritional quality of diet
• Improve QOL because the patient feels more in control of their eating and less overwhelmed or distressed by hunger, cravings, or a lack of satiety.

What Are the Challenges of AOMs?

• Most AOMS are expensive, and insurance coverage and cost may present an issue for patients.
• Some AOMs require dosing multiple times daily, which can become cumbersome and lead to missed doses.
• Some AOM side effects can be burdensome, especially when starting a new AOM or increasing the dose.
• Newer agents, such as semaglutide, can blunt appetite to such a degree that rapid weight reduction contributes to excessive loss of muscle mass. It can also lead to malnutrition if patients are not monitored and counseled appropriately.

Because obesity is considered a chronic disease, its treatment will likely require patients to take medications indefinitely. Given the serious nature of obesity, AOMs can provide significant benefits to health and quality of life for those living with obesity.

For more information on AOMS, see the Obesity Medicine Association Algorithm^® and the OMA Clinical Practice Statement on AOMs.