The Food and Drug Administration’s directory of prescription drugs has left out more than 9,000 medications. It also includes at least 34,200 other drugs that are either no longer sold or have errors in their listing, according to government inspectors.

These problems greatly limit the directory’s usefulness, according to a report by the Office of Inspector General of the Department of Health and Human Services. The directory is used in the handling of drug recalls, identifying medication errors and controlling imports.

Omissions and inaccuracies were primarily related to the failure of drug companies to comply with requirements to list their products with the FDA, the report found. The February 2005 directory listed 123,856 prescription drug products – more than three times the number listed in 1990.