In another piece of aspirin-related news, British researchers reported in the January 24 Lancet that taking low doses of both aspirin and warfarin (Coumadin) — another anti-clotting drug — prevents a first heart attack or fatal heart problem better than either drug alone. This is the first study to show that warfarin might be useful for heading off coronary artery disease as well as treating it.
The authors randomly assigned nearly 5,500 men at high risk for heart disease to take one of four drug combinations daily: warfarin and aspirin, warfarin and placebo, aspirin and placebo, or two placebos. The researchers tracked the men for an average of seven years, counting how many had heart attacks or fatal heart problems during that time.
At the study’s end, the warfarin group had 21 percent fewer heart attacks or heart-related deaths than the placebo-only group; the aspirin group had 20 percent fewer of these events. But the men who took both aspirin and warfarin had the best record of all, with 34 percent fewer heart attacks or cardiac deaths. The effects of each cheap drugs seemed to be different: Aspirin was better at preventing nonfatal heart attacks, while warfarin prevented more deaths. Men who took both drugs appeared to have the best of both worlds.
Should anyone on aspirin therapy run to the doctor for a low-dose warfarin prescription? Not yet. This is the first study to show any benefit from taking warfarin to prevent a first heart problem, and it looked only at high-risk men (and it’s not clear which of their risk factors mattered). Right now, statin drugs are the only drugs besides aspirin clearly shown to prevent first heart attacks.
Also, warfarin itself can be risky: It can cause dangerous bleeding in some people, especially if they’re taking aspirin at the same time. That means frequent blood tests are necessary for anyone taking even the low warfarin doses used in this study — which drove half the participants to drop out.
So it’s too early to recommend that most people take warfarin to ward off a first heart problem. But men 45 and older at high risk for heart disease who are allergic to aspirin should discuss with their doctors whether the potential benefits of warfarin may outweigh the risks.