Surgical risk from painkiller may be brief.

Physicians often advise patients not to use painkillers such as aspirin and ibuprofen in the week or so before a planned surgery because those drugs inhibit blood clotting and can increase the risk of serious bleeding in the operating room. A mere day's worth of abstinence from these painkillers may suffice, investigators now say.

To simulate steady use of ibuprofen, Neil Goldenberg and his two colleagues at the University of Colorado Health Sciences Center in Aurora gave 11 healthy, adult volunteers a 600-milligram dose of the drug three times daily for 7 days. They drew blood samples 40 minutes and then 8 and 24 hours after each volunteer took the final pill and tested each sample to see how quickly the blood's clot-forming particles, or platelets, would spring into action.

Most of the 40-minute samples clotted slowly, an indication of platelet dysfunction. The majority of samples harvested 8 hours after the last pill clotted at a speed within the normal range. A full day after the last use of ibuprofen, all volunteers' blood clotted at normal speed, the researchers report in the April 5 Annals of Internal Medicine.

The researchers caution that the test they used may not reflect actual bleeding risk in surgery and that ill people's blood may respond differently than that of healthy volunteers. Nevertheless, Goldenberg and his colleagues say, forgoing painkillers for several days or a week before surgery may not be necessary.

The researchers additionally observed that all three female volunteers who took oral contraceptives throughout the study showed no sign of platelet dysfunction, even 40 minutes after a dose of ibuprofen. Contraceptive drugs contain hormones known to promote clotting, the researchers note.--B.H.