A small but significant number of elderly people who began taking rofecoxib (Vioxx) had heart attacks in the first two weeks, a study has found. Previously the risk was thought to occur only after 18 months of treatment.

The study was posted online ahead of publication on 2 May by the CMAJ, the journal of the Canadian Medical Association (http://www.cmaj.ca/, doi: 10.1503/cmaj.051 679).

“A small proportion of patients using rofecoxib for the first time had their first MI [myocardial infarction] shortly after starting the drug,” the paper says. The risk was highest in the first six to 13 days (median nine days) after they started treatment with the drug. The risk did not increase …