Determining the date of manufacture of drug products from lot numbers.

Information necessary to determine the date of manufacture of many drug products from assigned lot numbers is presented. Eighty-four U.S. drug manufacturers were surveyed by mail. Response was received from 71 (85%) of the companies contacted, but only 34 provided the information necessary to determine the date of manufacture of their drug products from assigned lot numbers. Pharmacists can use this information to remove potentially deteriorated drug products from inventory.