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 distribution network". The price of specialty drugs compared to non-specialty drugs is very high, "more than $1,000 per 30-day supply". Specialty drugs cover over forty therapeutic categories and special disease states with over 500 drugs. Vogenberg claims that there is no standard definition of a specialty drug which is one of the reasons they are difficult to manage. "[T]hose pharmaceuticals that usually require special handling, administration, unique inventory management, and a high level of patient monitoring and support to consumers with specific chronic conditions, acute events, or complex therapies, and provides comprehensive patient education services and coordination with the patient