Hello Self medication particularly in edema cases is very dangerous . As you mentioned that OTC is not working , i.e. condition is not good . Reason of fluid or water retention in the body may be: 1 Renal disorder , diagnosis can be confirmed by ultrasound of both kidneys as well urine culture . 2 Congestive heart failure , this is the most common cause of water retention in body , so get in Echo as well clinical and physical examination by a physician . 3 Urticaria , as this is also most common cause . But , this is not possible to establish any diagnosis merely history of water retention. Other causes are hypoproteinaemia , anemia , drug reaction , renal failure . So I recommend you please consult a primary care physician and get his opinion. Good luck.