About 531,000 people who had records in a state agency’s hacked prescription-monitoring database will receive letters this week advising them to keep close watch on their credit record. The Virginia Department of Health Professions issued similar advice last month after the hacking of the Internet-accessed database surfaced April 30 but now is notifying people individually to take precautions.

Virginia Health Professions officials said they don’t have any evidence that personal information was stolen by hackers who accessed a Web site that collects data on some patient prescriptions. Nonetheless, the department is advising patients and providers who may have data in Prescription Monitoring Program files to be extra vigilant over the next 12 to 24 months in reviewing their financial statements and credit reports.

State and federal authorities said very little yesterday about a hacker’s claim that millions of patient prescription records kept on Virginia Department of Health Professions computers have been stolen. The FBI and the Virginia State Police have confirmed that an investigation is under way. But what is not clear is whether a hacker has been able to access a database with patient Social Security and driver’s license numbers as claimed in an extortion letter allegedly from the hacker.

State and federal authorities are investigating a possible extortion demand that seeks $10 million for the safe return of more than 8 million patient records and 35 million prescription records that allegedly were hacked last week from the Virginia Department of Health Professions computers. An extortion note posted on WikiLeaks, a Web site that publishes anonymous submissions and leaks of sensitive government and corporate information, reads: