This information is intended for information only. It is not a substitute for your doctor's instructions. Here we attempt to explain the differences between the different types of diet pills and weight loss drugs that are available by prescription. There are essentially 2 different kinds of weight loss actions employed by the different diet pills :

• Phentermine (Phentermine Hydrochloride) - Sympathomimetic family of appetite suppressants. Phentermine is the cheapest of the prescription diet pills. It is indicated to work for up to 3 months at which point the body builds up a resistance. Therefore it is useful for a quick start.
• Xenical(Orlistat) - Stomach lipase inhibitor (a fat blocker). Unlike other commonly prescribed weight-loss medications, Xenical is not an appetite suppressant and does not have a direct effect on the brain. Instead, it works in your digestive system to block about one-third of the fat in the food you eat from being digested. Enzymes in your digestive system, called lipases, help digest (or break down) fat. When taken with meals, Xenical attaches to the lipases and blocks them from breaking down some of the fat you have eaten. The undigested fat cannot be absorbed and is eliminated in your bowel movements.