A 68-year-old woman with hypertension, type 2 diabetes, and stage 3 chronic kidney disease (eGFR 45 mL/min/1.73 m²) is started on ramipril 2.5 mg daily. After 2 weeks, her serum creatinine rises from 1.4 mg/dL to 1.8 mg/dL, and potassium increases from 4.2 to 5.8 mEq/L. Urinalysis shows no proteinuria. What is the most appropriate management?