Hundreds of District residents who appear to be drug abusers are using Medicaid to buy excessive amounts of prescription drugs, and the city government is doing little to identify or stop them, according to a draft report by a federal inspector general.

According to the report, obtained yesterday, a federal audit of the D.C. Medicaid program identified 562 recipients suspected of abusing prescription drugs who received a total of more than 65,000 prescriptions at a cost of $730,862 to the program over a one-year period.

In these potential drug-abuse cases, the D.C. Department of Human Services had detected only 36 and had not taken any restrictive action, the report said.

The draft report was prepared by the U.S. Health and Human Services Office of Audit at the direction of HHS Inspector General Richard P. Kusserow.

HHS had warned the city government after a similar review in fiscal 1976 that it needed to improve detection of such drug abuse, and the city since has developed the computer capability to do so, the report said. But the city has not put this capability to good use, the report concluded.

"Chances remain good that recipient drug abusers will go undetected or, if detected, will not be prevented from continuing their patterns of abuse/misuse," the report said.

The report said the 562 potential drug-abuse cases were identified by studying the cases of any recipient of over 100 prescriptions in a year, and people who seemed to be using excessive amounts of drugs most prone to abuse, such as Valium, Percodan and Darvocet.

D.C. Human Services officials could not be reached immediately for comment on the report.

The draft report recommends that the D.C. Human Services office use its computer capability to identify aberrant use patterns, such as excessive amounts of prescriptions obtained, doctor shopping or pharmacy hopping.

It also said the city must follow up by restricting service to Medicaid recipients identified as abusers, preferably limiting the recipient to one physician and one pharmacy.