Myopathies creatine metabolism

Creatine is synthesized by the liver and, as creatine phosphate, is involved in supplying energy to a variety of cells particularly those in muscle. It is excreted as creatinine. Increased serum levels are found in myopathies and in conditions where the metabolic rate is raised, e.g. thyrotoxicosis. 

Exercise There is moxmting evidence that exercise might exacerbate statin-related side effects such as myopathy [50]. The randomised, controlled trial with 37 subjects (exercise plus simvastatin n= 18 exercise only n= 19) showed that simvastatin attenuates increases in cardiorespiratory fitness and skeletal muscle mitochondrial content when combined with exercise training in patients at risk of the metabolic syndrome [51]. The short-term administration of high-dose atorvastatin did not result in altered muscle function despite mild increases in creatine kinase levels [52]. 

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