What is the best medicine to treat capsular contracture?

Unfortunately there are no good medications for capsular contractures; especially very hard capsules.  Your best option is surgical.

Sorry to hear about the complications you have experienced. Capsular contraction can be a very frustrating complication for both patients and surgeons. In my practice, I have found the use of Accolate or Singulair to be helpful in some patients.  The most successful surgical treatment of these difficult problems has been with utilizing techniques such as sub muscular pocket conversion (if relevant), capsulectomy, use of fresh implants, and the use of acellular dermal matrix. Acellular dermal matrix is a biologic implant that carries the ability to become integrated into native tissue. It is made by taking a full thickness section of skin from a donor source ( human, porcine, or bovine in origin). I hope this, and the attached link.