One type of weight loss medication is "appetite suppressants." Appetite suppressants promote weight loss by tricking the body into believing that it is not hungry or that it is full. They decrease appetite by increasing serotonin or catecholamine, two brain chemicals that affect mood and appetite.
These drugs come in the form of tablets or extended-release capsules (pills that release medication over a long period of time). Appetite suppressants can be obtained by a doctor's prescription or bought over the counter. One common prescription appetite suppressant is phentermine. The FDA has also approved the appetite suppressant Belviq for long-term use in treating obesity. Side effects include dizziness, headache and tiredness.
Another type of prescription weight loss drug is a fat absorption inhibitor. They work by preventing your body from breaking down and absorbing fat eaten with your meals. This unabsorbed fat is eliminated in bowel movements.