How can i lose buttocks fatness fast using medicines ?

Can't be done: There is no spot fat loss. Choose a healthy weight loss program - for most people the best approach is to eat a low carbohydrate diet with plenty of good fats and lots of fresh vegetables. Then when you increase muscle mass you burn more fat so exercise.

No medicines.: There's no such thing as natural spot fat loss. You need to lose weight in general ; a certain % will be abdominal fat. Eat healthfully ; be physically active. Calories burned must > calories consumed. Exercises that work the buttocks include: lunges, squats, dumbbell squats, step ups, toe taps, plie, squats with kickbacks, hip extensions, one legged dead-lifts ; aerobic exercises.