Methadone Hydrochloride and water retention

I take many medications for different ailments. I started to have severe edema of feet, ankles, legs, thighs, and also face. I was precribed, depakote, lipitor, i cannot remember the name of the next one, but it was in addition to pepcid, and then methadone, all within 3 months of each other. The vicodin was discontinued at the same time the methadone was prescribed for chronic pain. In addition to this massive water retention, I also am having a difficult time voiding. I have Interstitial Cystitis and need to void every 10 minutes, so it is imperative that I can void easily. So two possible side affects, generalized edema and difficulty voiding. I take the methadone for severe chronic pain. And it or something elso has become a pain.