Severe muscle symptoms with lipid-lowering agents may be confused with neurogenic claudication associated with spinal canal stenosis.

BACKGROUND: Screening of the WHO global individual case safety report database (VigiBase) has recently identified case reports with HMG CoA reductase inhibitors and muscle symptoms co-reported with spinal stenosis. In some reports spinal stenosis appears to have been listed as a coincidental finding.

OBJECTIVE: To assess reports with sufficient information to ascertain if they suggested that there may have been diagnostic confusion between muscle symptoms attributable to HMG CoA reductase inhibitors with or without ezetimibe and symptoms of spinal stenosis.

METHOD: Reports were examined for patient demographics, past history, clinical and investigational findings, co-prescribed medicines and outcomes.

RESULTS: Three case histories recorded details suggestive of diagnostic confusion between severe and disabling muscle symptoms affecting the lower limbs attributable to an HMG CoA reductase inhibitor with and without ezetimbe and symptoms of neurogenic claudication due to spinal stenosis. The statins were not discontinued promptly leading to prolonged morbidity. Serum creatine kinase levels (CK) were normal in two patients and not recorded for the third.

CONCLUSION: The reports include two safety issues, firstly the need to consider HMG CoA reductase inhibitors as a cause of severe lower limb muscle symptoms even in the presence of spinal stenosis and normal CK levels and the second, the need to measure serum creatine kinase when these symptoms occur to detect progression of myopathy and potentially serious outcomes.