What is the underlying disease? FYI. For treating edema in patients with cardiac insufficiency, Lasix is prescribed at a dose of 20-50 mg per day. Depending on body reactions, Lasix dosage can be adjusted. During decongestant therapy for chronic kidney failure as well as for nephrotic syndrome, Lasix is used in the initial dose of 40-80 mg and is adjusted depending on patient body response. For patients on hemodialysis, the daily dosage of Lasix is 250-1500 mg.