Gemfibrozil-induced myositis in a patient with normal renal function

Area of Science:

• Pharmacology
• Clinical Medicine
• Toxicology

Background:

• Gemfibrozil is a lipid-lowering agent belonging to the fibrate class.
• Fibrates are generally associated with a low risk of myositis, myopathy, or rhabdomyolysis when used as monotherapy (1%).
• Previous literature documented gemfibrozil-related myositis in a patient with chronic renal failure and myopathy in a patient with normal renal function.

Observation:

• A 68-year-old male with normal renal function presented with a 6-month history of generalized body pain.
• Laboratory results revealed significantly elevated aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatine kinase (CK) levels.
• Gemfibrozil was discontinued, leading to a rapid decrease in CK, AST, and ALT levels and complete resolution of pain.

Findings:

• This case represents the first documented instance of gemfibrozil monotherapy-induced myositis in a patient with normal renal function.
• The Naranjo probability scale suggested a probable relationship between gemfibrozil use and the onset of myositis.
• Other potential causes of myositis were systematically excluded.

Implications:

• Clinicians should maintain awareness of the potential for gemfibrozil monotherapy to induce myositis, despite its low reported incidence.
• Patients presenting with myalgia while on gemfibrozil monotherapy may require discontinuation of the medication for symptom relief.
• This case underscores the importance of considering drug-induced myositis in patients with unexplained muscle pain and elevated muscle enzymes.