Pharmacologic Agents in the Management of Obesity

In the United States, the number of people who are overweight and obese is on the rise. In the U.S., 54.9% (97.1 million) of the adult population is overweight (including those who are obese), with 59.4% (50.2 million) of men being overweight and 50.7% (46.9 million) of women being overweight. In obesity, the statistics are grim, with 39.8 million (22.3%) obese individuals. Obesity is also on the rise in adolescent age groups. From 1988-1994, 11% of children (ages 6-11 years) and 11% of adolescents (ages 12-17 years) were overweight. Between 1991 and 1998, obesity increased in every state in the U.S. across ethnicities, genders, age groups, educational levels, and smoking statuses.

Health risks are associated with overweight and obese conditions. Adult deaths in the U.S. attributable to obesity are approximately 280,000 per year. Sixty-seven percent of persons diagnosed with type 2 diabetes mellitus have a body mass index (BMI) of greater than or equal to 27kg/m, and are therefore considered overweight. Forty-six percent of diagnosed type 2 diabetic patients have a BMI of greater than or equal to 30kg/m, and are by definition considered obese. The incidence of hypertension (mean systolic blood pressure greater than or equal to 140mmHg, mean diastolic blood pressure greater than or equal to 90mmHg) is 38.4% and 32.2% in obese men and women, respectively. There is no evidence of a direct correlation between obesity and cancer, but one study found that women who gained twenty pounds between 18 years of age and middle age had a higher risk of breast cancer compared with women who maintained a more stable weight.

Financial costs associated with overweight and obesity have reached astronomical levels. Americans spend $33 billion annually on weight-loss products and/or services. The total healthcare costs, direct (for example, medications, physician office visits) and indirect (lost wages, value of future earnings) total $99.2 billion.

What constitutes being overweight or obese? Body Mass Index (BMI) is a formula that is employed to assess the amount of excess adipose (fat) tissue. BMI is calculated by dividing the measured body weight (kilograms) by the height (meters squared). The National Institutes of Health (NIH) define overweight as a BMI of 25-29.9kg/m, and obesity as a BMI of 30kg/m or greater. A healthy weight range corresponds with a body mass index between 18.5 and 25kg/m.

In order to lose weight, an individual must expend more calories than are ingested. Decreasing the amount of calories along with increasing physical activity through regular exercise are appropriate methods to achieve weight loss. Changes in eating behavior such as eating more slowly and increasing the amounts of fresh fruits and vegetables in the diet also assist the individual in attaining a weight loss goal. Support group meetings, whether in person or online, is another nonpharmacologic method for helping individuals reach their goals.

Pharmacologic agents are reserved for obese patients (BMI>30kg/m) who are on a caloric reduction diet and exercise program. These agents may also be considered in situations where the patient is overweight (BMI>27kg/m), but also has other conditions associated with being overweight (Table 1). The pharmacologic agent chosen should be safe and effective for long-term use, have a favorable side effect profile, and free from abuse potential.Despite an increase overweight and obesity in children and adolescents, there are no studies that have demonstrated the safety and efficacy of any weight loss drug in these populations.An overview of the pharmacologic agents for weight loss includes the anorexiants, serotonin/norepinephrine agonist, and lipase inhibitors.