Statin-Associated Myopathy with Normal Creatine Kinase Levels

Abstract

Some patients who develop muscle symptoms while receiving statin therapy have demonstrable weakness and histopathologic findings of myopathy despite normal serum creatine kinase levels.

Ezetimibe-associated myopathy in monotherapy and in combination with a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor

“…Interestingly, muscle biopsies showed evidence of mitochondrial dysfunction, including increased lipid stores, fibres that did not stain for cytochrome oxidase activity and ragged red fibres. These pathological and biochemical findings in patients with statin myotoxicity suggest impaired fatty acid oxidation (14). These findings reversed when the patients were no longer receiving statin therapy.…”

“…Phillips et al (14) reported patients who developed muscle symptoms but had a normal CK concentration while receiving statin therapy. These patients had demonstrable weakness measured by standard techniques of functional capacity and muscle strength.…”

“…These findings reversed when the patients were no longer receiving statin therapy. Thus, serum CK concentration may not be truly predictive of statin-associated myopathy (14). The same group reported that 18 patients over 30 years of age had myopathic symptoms on ezetimibe alone within two weeks of beginning therapy (15).…”

Statin intolerance: more questions than answers

“…In 1995, a leading lipidologist expressed an opinion that about 5% of people taking lovastatin developed some kind of myopathy 'with or without elevation of muscle enzyme levels' [3]. In 2002, Phillips et al described biopsy-proven myopathy accompanied by weakness in statin-treated patients without elevations of serum creatine kinase (CK) [4]. Lovastatin has been shown to potentiate post-exercise CK elevation, and clinical experience has suggested interaction between statins and exercise in muscle adverse effects [5,6].…”

The structure of optimal statin initiation policies for patients with Type 2 diabetes

“…Historically, the primary goal of managing Type 2 diabetes has been the control of blood glucose levels; however, more recently, the importance of cardiovascular risk has been emphasized (The United Kingdom Prospective Diabetes Study (UKPDS) Group 1998. (Phillips et al, 2002, Pasternak et al, 2002. However, none of the published guidelines explicitly consider the trade-off between the benefits of reduction in CHD and stroke risks and the adverse side effects of treatment.…”