Obesity Therapy: How and Why?

BACKGROUND: Obesity represents the second preventable mortality cause worldwide, and is very often associated with type 2 Diabetes Mellitus (T2DM). The first line treatment is lifestyle modification to weight-loss, but for those who fail to achieve the goal or have difficulty in maintaining achieved results, pharmacological treatment is needed. Few drugs are available today, because of their side effects.

OBJECTIVE: We aim to review actual pharmacological management of obese patients, highlighting differences between Food and Drug Administration - and European Medicine Agency-approved molecules, and pointing out self-medications readily obtainable and widely distributed.

METHODS: Papers on obesity, weight loss, pharmacotherapy, self- medication and diet-aid products were selected using Medline. Research articles, systematic reviews, clinical trials and meta-analyses were screened.

RESULTS: Anti-obesity drugs with central mechanisms, such as phentermine and lorcaserin, are available in USA, but not in Europe. Phentermine/topiramate and naltrexone/bupropion combinations are now available, even though the former is still under investigation from EMA. Orlistat, with peripheral mechanisms, represents the only drug approved for weight reduction in adolescents. Liraglutide has been approved at higher dose for obesity. Anti-obesity drugs, readily obtainable from the internet, include crude-drug products and supplements for which there is often a lack of compliance to national regulatory standards.

CONCLUSIONS: Mechanisms of weight loss drugs include the reduction of energy intake or the increase in energy expenditure and sense of satiety as well as the decrease of hunger or the reduction in calories absorption. Few drugs are approved, and differences exist between USA and Europe. Moreover, herbal medicines and supplements often sold on the internet and widely used by obese patients, present a risk of adverse effects.