A 58-year-old man with a 10-year history of osteoarthritis of the knee presents with severe joint pain. He has been taking ibuprofen 400 mg three times daily for the past 6 months with good symptomatic relief. On examination, he has a blood pressure of 148/92 mmHg (previously 130/80 mmHg 6 months ago). His serum creatinine has risen from 0.9 mg/dL to 1.4 mg/dL, and urinalysis shows mild proteinuria. He denies any other systemic symptoms. What is the most appropriate next step in management?