a 57-year-old woman with cirrhosis complains of worsening distension of the abdomen and edema up to her lower legs despite compliance with eating less than 2 grams daily of sodium. she denies abdominal pain, constipation, dyspnea or fevers. on exam, her abdomen is distended and has a notable fluid wave. she has 2 pitting edema to the level of her ankles. which medication is the most appropriate next step in the management of this patient?