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 are often defined as specialty because their price is much higher than that of non-specialty drugs. Medicare defines any drug for which the negotiated price is $670 per month or more, as a specialty drug which is placed in a specialty tier that requires a higher patient cost sharing. Drugs are also identified as specialty when there is a special handling requirement or the drug is only available via a limited distributions network. By 2015 "specialty medications accounted for one-third of all spending on drugs in the United States, up from 19 percent in 2004 and heading toward 50 percent