I have been taking Polycitra (branded) or Cytra-K (generic) crystals for more than 20 years, to prevent a recurrence of uric acid kidney/bladder stones. Now my drugstore (CVS) has stopped selling them, they say their distributor no longer carries them. Has that medication gone out of production completely? If so, is there a new product that is intended to replace it? If I have to stop taking it, am I likely to have the stones come back? Thank you for your advice.