Decreases in serum ubiquinone concentrations do not result in reduced levels in muscle tissue during short-term simvastatin treatment in humans*

Statins, which are commonly used drugs for hypercholesterolemia, inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme in cholesterol synthesis. Important nonsterol compounds, such as ubiquinone, are also derived from the same synthetic pathway. Therefore it has been hypothesized that statin treatment causes ubiquinone deficiency in muscle cells, which could interfere with cellular respiration causing severe adverse effects. In this study we observed decreased serum levels but an enhancement in muscle tissue ubiquinone levels in patients with hypercholesterolemia after 4 weeks of simvastatin treatment. These results indicate that ubiquinone supply is not reduced during short-term statin treatment in the muscle tissue of subjects in whom myopathy did not develop.