I need to lose 15 pounds in a week. I weight 150 and im 5'2". What can I do? What diet pills do you recommend? Does grapefruit help to lose weight?

Probably wont happen. Probably won't happen unless you starve yourself and don't eat anything for a week. Even then, losing 10% of your body weight in one week is very unhealthy. Diet pills like Phentermine don't so much burn calories as they do curb appetite. Laxatives and diuretics will cause dehydration and electrolyte abnormalities and possibly arrhythmias. Rethink plan and try 15 lb over 3 months probably safer.
Lose 2 lbs this week. Helpful diets include natural foods that take time to chew but contain few calories. Examples include carrots, celery, and iceberg lettuce (without salad dressing). When shopping for fruits, buy small ones no bigger than a tennis ball, because fruits contain natural sugar. Drinks without calories include water and green tea. A calorie is a calorie, regardless of where it comes from. No diet pills.