U.S. Food and Drug Administration (FDA) Approved Weight Loss Medications and the Management of Obesity in Adults

syDney saDkin, PharMD, PGy-1 aCute Care— aMBulatory Care foCuseD PharMaCy resiDent

alleGheny health network, alleGheny General hosPital, PittsBurGh, Pa

Background

Obesity is a chronic disease that affects more than 4 in 10 adults in the United States.2 This disease state is characterized by a multitude of factors including an elevated BMI, elevated waist circumference and comorbidity risk. The threshold for BMI is > 25 kg/m2 or > 23 kg/ m2 for certain ethnicities. Waist circumference thresholds for abdominal obesity vary based on the population and the organization; however, for the American Heart Association (AHA) an elevated waist circumference in men is > 40 inches and > 35 inches in women.1 Weightrelated diseases or complications include, but are not limited to, prediabetes, metabolic syndrome, type 2 diabetes, dyslipidemia, hypertension, cardiovascular disease, obstructive sleep apnea, asthma, osteoarthritis, urinary stress incontinence and depression. The interpretation of these components contributes to the classification of obesity into different classes, ultimately guiding the overall management approach.1

Treatment Approaches

There are various treatment approaches including non-pharmacologic and pharmacologic to aid in weight loss management; however, for those that are indicated, research has found clear benefit in utilizing a combination of these approaches in long-term management and success. Non-pharmacologic recommendations are also commonly referred to lifestyle and behavioral therapy. Effectively designed programs consist of a healthy meal plan, physical activity and behavioral interventions.1 These interventions are effectively executed by a multidisciplinary team consisting of dieticians, nurses, educators, physical activity trainers and clinical psychologists. Within Allegheny Health Network, pharmacists are a crucial part of the multidisciplinary team in the ambulatory setting. Grade A recommendations include a reduced-calorie meal plan that is high in macronutrients which supports the evidence that reducing total energy intake should be the main component of any weight-loss intervention. Focusing on increasing the macronutrient composition has been found to optimize adherence, eating patterns, weight loss, metabolic profiles, risk factor reduction and clinical outcomes.1 Grade A recommendations for physical activity include > 150 min/week of moderate exercise performed during 3 to 5 daily sessions per week.1 Resistance training should be advised; however, physical activity should be individualized to the patient based on capabilities and preferences.1 For the behavioral component this can be effectively executed by integrating goal-setting, education, stress reduction and counseling. There are five FDA approved medications for weight management. Short term treatment of 3 to 6 months has not demonstrated long term health benefits with the current evidence (Grade B)1; therefore, the pharmacologic agents recommended should be individualized for the patient based on efficacy, side effects, cautions and warnings. The effectiveness of weight loss medications is defined as > 5% weight loss after 3 months use as this is the threshold for experiencing metabolic benefits. If the response is insufficient, discontinuation of the medication is considered, and alternative medications and approaches are evaluated.3

Pharmacologic Options

Wegovy (semaglutide) and Saxenda (liraglutide) are glucagon-like peptide-1 (GLP-1) receptor agonists. They mimic the GLP-1 hormone that is a physiological regulator of appetite and caloric intake. This receptor is present in several areas of the brain involved in appetite regulation.4 Through the stimulation of insulin secretion, reduction of glucagon secretion and decreasing of the appetite, these medications have shown benefit in weight reduction. These are injectable medications that are dosed either once weekly for Wegovy or once daily for Saxenda. Common adverse reactions of these medications can include nausea, vomiting, diarrhea, constipation, dyspepsia and abdominal pain. GLP-1 agonists are contraindicated in patients with a personal or family history of medullary thyroid carcinoma or in patients with Multiple Endocrine Neoplasia syndrome type 2.1, 4 They should also be avoided in patients with a history of pancreatitis, in females and males of reproductive potential and in pregnancy.4

Contrave (naltrexone HCl/bupropion HCl) is an oral combination medication that is also FDA approved for weight loss. Naltrexone HCl is an