Review Question - QID 109272

A 64-year-old woman presents to the emergency room with whole-body itching. She noticed her symptoms while in the bathtub at home. She has never had symptoms like this before. Over the previous several months she has had episodes of joint swelling and pain in her hands as well as redness, burning pain, and swelling of her hands and feet. Her medical history is significant for type 2 diabetes mellitus, hypertension, and osteoporosis for which she takes metformin, enalapril, and alendronate. She was found to have a deep vein thrombosis of her left leg 3 months prior to presentation. Her temperature is 98.6°F (37.0°C), pulse is 80/min, blood pressure is 135/85 mmHg, and respirations are 13/min. Physical exam is notable for a woman in discomfort with excoriations over the skin on her forearms. Laboratory tests are shown below.

Serum:
Na+: 135 mEq/L
Cl-: 100 mEq/L
K+: 5.0 mEq/L
HCO3-: 22 mEq/L
BUN: 19 mg/dL
Glucose: 130 mg/dL
Creatinine: 1.0 mg/dL

Hematocrit: 64%
Leukocyte count: 19,000 cells/mm^3 with normal differential
Platelet count: 900,000/mm^3

Which of the following is the most appropriate long-term treatment?