A 52-year-old woman with a history of acute myocardial infarction 3 months ago is on dual antiplatelet therapy and lisinopril. Her current lipid profile shows: LDL-C 95 mg/dL, HDL-C 38 mg/dL, triglycerides 180 mg/dL. She was started on atorvastatin 40 mg daily 2 months ago. On review, she reports new-onset muscle pain in her thighs and calves, worse with exertion. Creatine kinase is 1200 U/L (normal < 200). What is the most appropriate management?