The effect of statins on muscle CoQ10 may be drug and
dose dependent. In a recent trial using simvastatin 80
mg/day, atorvastatin 40 mg/day, or placebo for 8 weeks (5),
mean muscle concentrations of CoQ10 in the simvastatintreated
patients decreased by 34%. To date, this is the only
trial comparing intramuscular CoQ10 levels among the
statins.
There are few published studies on intramuscular CoQ10
levels in subjects symptomatic from statin myopathy. Almost
half (47% or 17 of 36 patients) of patients referred for
myopathic complaints presumably due to statin-associated
myopathy had intramuscular CoQ10 levels 2 standard
deviations below the mean (G. Vladitu, personal communication,
August 26, 2005). It is not clear, however, whether
these decreased intramuscular CoQ10 levels produced statin
myopathy or were simply associated with a reduction in
mitochondrial volume associated with the statin myopathy
itself (5) or associated with physical inactivity due to
myopathic symptoms. A recent study (36) examined intramuscular
CoQ10 levels in patients with statin-associated
myopathy and found levels 2 standard deviations below the
normal mean in 3 patients, below 1 standard deviation in 7
patients, normal levels in 4 patients, and increased levels in
4. No evidence of myocyte apoptosis was found, using
terminal deoxynucleotidyl transferase-mediated deoxyuridine
triphosphate nick-end labeling assay and immunohistochemical
studies with antibodies against Bax, Bcl-2, and
caspase-3, although only 11 biopsies had enough tissue to perform the test.