Use of generic medications continues to increase, according to Express Scripts, the pharmacy benefit management company. More than 50 percent of all prescriptions that Express Scripts fills are for generics.

Still, the generic fill rate varies widely across the country, with possible explanations including variations "in prescribing patterns, state regulations, differences in disease prevalence, and varying use of drug benefit designs that encourage greater use of generics," according to the company.

Express Scripts bases its findings on a review of claims for outpatient pharmacies and eligibility data from a random sample of about 3 million commercially insured people.

SOURCE: EXPRESS SCRIPTS