Computers have reduced medical errors by making prescriptions clearer and more legible but some do not warn doctors of potentially deadly problems, British researchers said on Friday.

About 95 percent or more of prescriptions from family doctors in Britain are issued on computers, so previous problems such as difficult to read handwriting or unclear doses are no longer an issue.

But computer programs do not issue alerts to doctors for contraindications or other conditions for which the medication should not be prescribed.

“The computer has the potential to help us even more in terms of trying to prevent us from making mistakes, but at the moment that potential is not being realized,” Professor Anthony Avery, of the University of Nottingham, said in an interview.

The wrong drug combinations, for example prescribing oral contraceptives for a patient with a history of deep vein thrombosis or blood clots, could be deadly.

“Patients are being admitted to hospital and dying, although not in large numbers, as a result of contraindication prescribing,” he added.

Avery and his colleagues and researchers at the University of Edinburgh in Scotland tested four computer systems being used by about three quarters of general practitioners. All of the systems failed to detect known prescribing errors, especially where drugs were contraindicated.

“The good news is that it (the problem) can be overcome without too much difficulty,” explained Avery, who reported the results in the British Medical Journal.

Computers have databases on drugs and conditions for which they should not be prescribed but there has not been a systematic way for the computer suppliers to make the links between the patient’s prescription and contraindications.

“It is going to take some time but having identified this problem, there is a fairly straightforward solution,” Avery said.

“It is something that could help prevent serious problems in the future.”

Robin Ferner, director of the West Midland Center for Adverse Drug Reaction Reporting in Birmingham, England, said computers have already reduced prescribing errors by as much as 60 percent.

“Contraindications account for about four percent of adverse drug events in general practice. The systems could be improved. They might list every contraindication to a drug whenever it was prescribed,” he said in a commentary in the journal.

SOURCE: British Medical Journal, May 15, 2004.