Potential and actual drug product selection rates in Florida.

A systematic review of new prescriptions conducted 1 year after the enactment of Florida's drug product selection law showed that 36.3% were potentially subject to product interchange. Product interchange actually occurred in only 6.2% of these potentially eligible prescriptions. Positive formularies established by the pharmacies reduced the eligible population to 8.1% of all new prescriptions and the product selection rate relative to these formularies was 14.7%. Twenty drugs accounted for nearly three-fourths of all drug product selection activity.