Coenzyme Q10 be measured in blood plasma, these measurements reflect dietary intake rather than tissue status. Currently, most clinical centers measure CoQ levels in cultured skin fibroblasts, muscle biopsies, and blood mononuclear cells. Culture fibroblasts can be used also to evaluate the rate of endogenous CoQ biosynthesis, by measuring the uptake of C-labelled "p"-hydroxybenzoate. CoQ shares a biosynthetic pathway with cholesterol. The synthesis of an intermediary precursor of CoQ, mevalonate, is inhibited by some beta blockers, blood pressure-lowering medication, and statins, a class of cholesterol-lowering drugs. Statins can reduce serum levels of CoQ by up to 40%. CoQ is not approved by
Specialty drugs in the United States not only costs more, but they also take longer to develop than other large market pharmaceuticals (See Drug development). In addition, there are often fewer drug choices for rare or hard-to-treat diseases. This results in less competition in the marketplace for these drugs due to patent protection, which allows these firms to act as monopolists (See Drug Price Competition and Patent Term Restoration Act). Due to this lack of competition, policies that serve to limit prices in other markets can be ineffective or even counter-productive when applied to specialty drugs. High prices for specialty drugs are a problem for both