A 58-year-old man with diabetes mellitus presents to the emergency department with acute kidney injury following a contrast-enhanced coronary angiography performed 48 hours ago. Serum creatinine has risen from 1.8 mg/dL to 4.2 mg/dL. Urinalysis shows muddy brown casts and fractional excretion of sodium (FENa) is 2.1%. He is euvolemic on clinical examination. What is the drug of choice to prevent progression of contrast-induced acute tubular necrosis?