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 and prescribe." Drugs are most typically defined as specialty because they are expensive. They are high cost "both in total and on a per-patient basis". High-cost medications are typically priced at more than $1,000 per 30-day supply. The Medicare Part D program "defines a specialty drug as one that costs more than $600 per month". Most of the prescriptions filled by Pennsylvania-licensed Philidor Rx Services, a specialty online mail-order pharmacy, which mainly sold Valeant Pharmaceuticals International Inc expensive drugs directly to patients and handled insurance claims on the customers' behalf, such as Solodyn, Jublia, and Tretinoin, would be considered specialty