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 but some—such as Pfizer and Amgen—are also developing biosimilars." In 2013 AfPA director David Charles published an article on specialty drugs in which he agreed with the findings of the Congressional Budget Office that spending on prescription medications "saves costs in other areas of healthcare spending". He observed that specialty drugs are so high priced that many patients do not fill prescriptions resulting in more serious health problems increasing. His article referred to specialty drugs such as "new cancer drugs specially formulated for patients with specific genetic markers". He explained the high cost of these "individualized medications based on diagnostic