The pharmacotherapy of obesity

Obesity is considered the most concerning and blatantly visible--yet most neglected--public health problem by the WHO. The steadily increasing number of overweight and obese people has reached 2.3 billion and 700 million worldwide, respectively. Obesity is a complex condition, one that presents serious health risks with respect to type 2 diabetes, ischemic heart disease, and hypertension, therefore controlling the global obesity epidemic decreases not only health problems, but also expenditure. The underlying cause of obesity is a metabolic disorder of genetic, central nervous system or endocrine etiology that manifests in increased nutritional intake and/or decreased physical activity ultimately leading to excessive lipogenesis. The natural treatment of obesity, that is often advised, is comprised of healthy lifestyle choices, namely low-calorie diet and exercise. However, the pharmaceutic treatment of obesity is just as important; having a better compliance rate, anti-obesity drugs also improve quality of life and patient-care outcome concerning accompanying diseases. In most countries only one drug is currently available against obesity: orlistat, which is a specific and irreversible lipase inhibitor. One of the reasons for the scarce number of anti-obesity drugs is the complex pathomechanism involved in obesity. Interference with the intricate biochemical processes that govern alimentation may lead to widespread adverse effects. The advances of the field however, have prompted novel drug leads. In the past few years FDA has approved new drugs for the treatment of obesity, recently liraglutide in 2014. The approval of drug combinations, such as phentermine/topiramate and bupropion/naltrexone are also noteworthy, the components of which have been previously approved, but not necessarily for obesity as main indication. Furthermore, there are many anti-obesity drug candidates currently in clinical phase trials, with promisingly modest adverse effect profiles; hence the expansion of the anti-obesity agents in the near future can be foreseen. The present work summarizes the central and peripheral regulatory pathways of energy consumption, nutrition, and appetite. The possible drug targets, the currently available and novel anti-obesity agents, and the new trends in obesity research are also discussed.