Well, I'm not an export on weight loss drugs, just a guy who goes to gym a lot. I'll try my best to give you some information. You should check with GNC staffs for more information, and get some suggestions from your family doctor.
1.there are some fat blocker drug, which will prevent your body from absorbing the fat in food.
2.some drugs will make your hart rate go 5-10% higher, and body tempreature 0.5 degress higher, so, you will burn more calories.
3.some food replacement thing like "slim fast", just provide you really low fat food.
But, to my exprience, drugs can only acting as a good assistance, go to gym is the best way. Health and fitness is not just about how much you weight, or the size or the pants. Sports will keep you in shape, and with lots of energy. Good luck.