The following table uses WHO diagnostic criteria to forecast the prevalence of obese and overweight people in seven major national markets from 2001 to 2008.

Short-term treatment of obesity with drugs is generally not warranted because obesity is a chronic condition that requires long-term treatment. Current drug therapy for weight loss is limited, with only three drugs prescribed for obesity: phentermine, a short-term therapy, and orlistat and sibutramine, both suitable for long-term treatment.
However, scientists have established five classes of drugs that could potentially treat obesity and weight gain:
- appetite suppressants - drugs that act centrally on the noradrenergic and serotoninergic pathways in the brain to reduce hunger perception, increase satiety and inhibit food intake. Phentermine is an example of a short-term appetite suppressant that inhibits noradrenaline re-uptake, while sibutramine is a long-term drug that inhibits serotonin and noradrenaline re-uptake;
- fat absorption inhibitors - drugs that reduce energy intake through a peripheral route, such as the gastrointestinal tract. Orlistat is an example of a fat absorption inhibitor that inactivates the pancreatic enzyme, lipase, so that dietary fat is not absorbed by the body;
- metabolic enhancers -  drugs that act through peripheral mechanisms to increase
thermogenesis without the need for an increase in physical activity. Currently, there are no drugs that safely enhance energy expenditure;
- fat mobilizers -  drugs that act peripherally to reduce fat mass or decrease triglyceride synthesis. Leptin is currently in clinical trials and targets the OB receptor to reduce food intake and mobilize adipose mass;
- gene therapy -  antibodies that can induce adipocyte cell death.

Pharmacotherapy is generally only recommended in obese patients with a BMI>30kg/m2 or in patients with a lower BMI who have android obesity (the type more commonly associated with serious morbidity and mortality). It should not be considered as a replacement for diet, behavioral modification and exercise, but rather as an adjunct for use in conjunction with these techniques.

Reductil (brand name Meridia in North America) was the major product in Boots Pharmaceuticals. pipeline until Knoll acquired Boots Pharmaceuticals. operations in April 1995. Abbott gained Reductil through its acquisition of Knoll in 2001. Sibutramine is indicated for the treatment of obesity in patients whose BMI is above 30, or above 27 in the presence of other cardiovascular risk factors, such as hypertension, diabetes or dyslipidemia. It belongs to a new class of drugs, serotonin and norepinephrine reuptake inhibitors (SNRIs), used in the treatment of obesity. The drug works by increasing satiety and metabolic rate by the inhibition of serotonin and noradrenaline uptake, reducing the amount of food eaten by enhancing the feeling of fullness. Unlike Pondimin (fenfluramine), which was withdrawn in 1997 due to unfavorable side effects, Reductil has no reported association with primary pulmonary hypertension, the major side effect of SNRIs. However, sibutramine is associated with anorexia, constipation, insomnia, headache and hypertension. It is not indicated for patients with a history of coronary heart disease, congestive heart failure, arrhythmia or stroke. It is also not recommended for patients with severe hepatic dysfunction or renal impairment. Although Xenical has a greater patient potential than Reductil due to its mechanism of action, it suffers from gastrointestinal side effects. In particular, fecal leakage after a meal with high fat content can diminish patient compliance.
Abbott is well placed to maximize the market potential of Reductil, having mounted an extensive DTC campaign and benefiting from the drug.s presence in the diabetes monitoring market. The company recorded sales of $272m for Reductil in 2002, up from $202m in 2001 despite bad publicity. Sales in 2004 was $352m. Assuming that Abbott can provide sufficient proof that Reductil is safe, and in light of the lack of alternative prescription therapies, sales of Reductil are forecast to grow to $425m in 2008.

Reductil (brand name Meridia in North America) was the major product in Boots Pharmaceuticals. pipeline until Knoll acquired Boots Pharmaceuticals. operations in April 1995. Abbott gained Reductil through its acquisition of Knoll in 2001. Sibutramine is indicated for the treatment of obesity in patients whose BMI is above 30, or above 27 in the presence of other cardiovascular risk factors, such as hypertension, diabetes or dyslipidemia. It belongs to a new class of drugs, serotonin and norepinephrine reuptake inhibitors (SNRIs), used in the treatment of obesity. The drug works by increasing satiety and metabolic rate by the inhibition of serotonin and noradrenaline uptake, reducing the amount of food eaten by enhancing the feeling of fullness. Unlike Pondimin (fenfluramine), which was withdrawn in 1997 due to unfavorable side effects, Reductil has no reported association with primary pulmonary hypertension, the major side effect of SNRIs. However, sibutramine is associated with anorexia, constipation, insomnia, headache and hypertension. It is not indicated for patients with a history of coronary heart disease, congestive heart failure, arrhythmia or stroke. It is also not recommended for patients with severe hepatic dysfunction or renal impairment. Although Xenical has a greater patient potential than Reductil due to its mechanism of action, it suffers from gastrointestinal side effects. In particular, fecal leakage after a meal with high fat content can diminish patient compliance.Abbott is well placed to maximize the market potential of Reductil, having mounted an extensive DTC campaign and benefiting from the drug.s presence in the diabetes monitoring market. The company recorded sales of $272m for Reductil in 2002, up from $202m in 2001 despite bad publicity. Sales in 2004 was $352m. Assuming that Abbott can provide sufficient proof that Reductil is safe, and in light of the lack of alternative prescription therapies, sales of Reductil are forecast to grow to $425m in 2008.

Report is sourced from Reuters Business Insight

• Obesity Drug Markets (14/10/2008)
• Valuing Pharmaceutical Innovation (14/10/2008)
• Novel Therapeutic Approaches in Cardiovascular Medicine (09/10/2008)

• Clinical Research (14/07/2006)
• CEFTA (12/03/2006)
• Safety Assessment (01/01/2006)

• Business Development (09/08/2004)