I have been taking Zoloft or Sertraline (150 mg daily) for about 7 yrs now. It has worked very well until recently. My last prescription refill the sertraline color changed from a yellowish/tan color to a light green and it also changed in shape. Would this change have anything to do with the drug not working? Or do I need to think about changing prescriptions? It just seems odd that the two events happened at the same time.