Obesity management or Weight reduction can be achieved in 4 ways

• Dietary modifications
• Physical exercise
• Medications
• Surgery

Of these first two are the safest and most efficient. Medications are considered only as a next stage. Commonly not a huge success rate is achieved with these medications and also because of potential side-effects, anti-obesity medications are prescribed only when the benefits outweigh the risks associated with it.

Mechanism of action:

Anti-obesity medications act through one or a combination of the following mechanisms

1. Appetite suppression, for eg. Catecholamines and their derivatives.
2. Interference with absorption from the intestine, eg Orlistat
3. Increase of body’s metabolism.

Orlistat:

Orlistat(Xenical) decreases intestinal absorption  of fat by inhibhiting the enzyme Pancreatic Lipase.

Adverse effects: Steathorrhoea, which is due to frequent oily bowel movements. It can be minimized by reducing fat intake in the diet.

Sibutramine:

Sibutramine(Reductil/Meridia) is an anorectic(appetite suppressant)  which decreases the desire to eat.

Adverse effects: Increased blood pressure, headache, dry mouth, constipation and insomnia.

Rimonabant

Rimonabant(Acomplia) is one of the recently developed drugs. It has both central action(appetite suppression) as well as peripheral action. Peripherally it increases thermogenesis resulting in increased energy expenditure. Besides causing weightloss it helps in reversing the metabolic effects of obesity( like insulin resistance and hyperlipidemia).  However the results are not higher compared to other medications.  However it has not been approved for use in either US or Canada.

Pramlintide

Pramlintide(Symlin) is a synthetic analogue of hormone Amylin, which is secreted by pancreas in response to eating. It also delays  gastric emptying and promotes a feeling of satiety. However, it  is permitted to be used only for Diabetic patients (both type 1 and type 2) , who are on insulin treatment.  Currently it is being tested for use in Non-diabetic patients. Another drawback is that it needs to be injected after meals.

Exenatide

Exenatide(Byetta) is a long standing analogue of  GLP-1 (GLP-Glucagon Like Peptide) which is an intestinal  hormone secreted in response to food intake. It decreases appetite, delays gastric emptying and promotes feeling of satiety. But again the results vary from individual to individual and have not been consistent. Also it is advisable for use only in people with Type 2 Diabetes Mellitus. It needs to be injected twice daily and patients have reported severe nausea after the dose.

Metformin

It is a peripherally acting drug which helps in improving insulin sensitivity, used in treatment of Type 2 Diabetes Mellitus. It even decreases appetite and also absorption of nutrients from intestine.