Best diet pills out there!!?

So I need to lose wight fast because I wanna be able to go to the beach wearing a bikini. What are the best pills out there to lose weight? I used to take this chinise ones that worked really welll but I ran out and threw away the container so I don't remember what they were call. But now I'm ready to try something different I just want to know which ones are the best. I am 5'4 and my weight is about 180lbs. People tell me my weight is all in my butt. I have a big one but I still feel like I'm a whale.