My dad is getting pain management shots in his back for pinched nerves. Mediction injection is primarily steroids which cause fluid retention. Also has a hx of CHF that causes extremity swelling. He is on Lasix 20 mg. Because he hasn't been getting sleep due to an overactive bladder secondary to hx of prostrate cancer, he went to the Urologist for suggestions. The Urologist prescribed Sanctura XR, aka trospium chloride to reduce his urge to go. Isn't this medication negating the effects of the Furosimide, causing him to retain more fluid?