| Muscle weakness or pain can be a symptom of rhabdomyolysis,
and the patient should contact their healthcare provider. |
| Myopathy and rhabdomyolysis are the main concerns when taking Simvastatin.
Myopathy is a muscular disorder that is characterized by muscle weakness
due to faulty muscle fibers. Rhabdomyolysis is a more serious development.
Rhabdomyolysis is caused when muscle fibers break down and leak out their
possibly toxic cellular contents. These toxins enter the circulatory system
and can lead to renal failure. Along with cholesterol, the HMG-CoA pathway
also produces isoprenoids, which are important in cellular functions, such
as electron transfer in the mitochondria and glycosylation of cell surface
proteins. Simvastatin also stops the production of these isoprenoids. |
| The mechanism through which simvastatin induces muscle disorders is
not fully understood. Some studies suggest that simvastatin increases the
fluidity of the muscle membrane, or induces fiber necrosis. Other studies
suggest that the myotoxicity is because of the low levels of Ubiquinone
(CoQ10) in the mitochondria. This has been supported my muscle biopsies. |