A 76-year-old woman, L.R., is seen in your hospital for a hot, painful, red, swollen leg injury. Deep vein thrombosis is ruled out by ultrasound. L.R. is diagnosed with superficial venous thrombosis and compression stockings are prescribed. L.R. maintains her varicose vein problem worsened significantly when she started nisoldipine (Sular, First Horizon Pharmaceutical) for blood pressure control. L.R.'s physician asks you about this possibility. He also asks you to recommend an alternative drug (to nisoldipine) for L.R.'s hard-to-control hypertension. She currently takes valsartan (Diovan, Novartis) 320 mg, hydrochlorothiazide (HCTZ) 50 mg, plus nisoldipine 20 mg/d. Her BP averages 145/90. Her only other medicine is prednisone 2 mg. What do you recommend?