Careful compliance makes management of anticoagulant and antiplatelet drugs safer.
If you have atrial fibrillation and have been prescribed an anticoagulant such as warfarin (Coumadin), there may come a time when your doctor will consider adding another type of blood thinner, called an antiplatelet agent, to your anti-clotting regimen. Examples of antiplatelet agents include aspirin, clopidogrel (Plavix), and prasugrel (Effient).
Each kind of blood thinner paralyzes a different part of the blood-clotting process. Taking them together doubles your risk of a dangerous hemorrhage. But some people need both kinds of blood thinners because they are at high risk of blood clots—which can lead to the most common kind of stroke.
When you weigh those risks, the chance of bleeding is less worrisome than the risk of stroke. But there’s no way around it: serious risks remain, says Dr. Daniel Singer, Harvard professor of medicine and an expert in the prevention of stroke in atrial fibrillation patients. “If the anticoagulant causes you to bleed into or around the brain, the outcomes are just terrible. These events are relatively rare, but they are the most devastating toxic effect of these drugs,” he says.
What’s your CHADS2 score?
It’s a simple way to estimate stroke risk:
Complicating the situation is the recent approval of many new anti-clotting agents, offering a bewildering variety of choices.
And there’s no one-size-fits-all formula for adding antiplatelet to anticoagulant therapy. Different doctors will prescribe different drug combinations at different doses in different patients for different lengths of time. Treatment has to be highly individualized based on a person’s particular risk factors.
You and your doctor should work together to balance your bleeding risk against your clotting risk. Here’s how it works.
Making it safer
People with atrial fibrillation should know their CHADS2 score. Those with a CHADS2 score of 0 can choose not to take any anti-clotting therapy.
Those with a CHADS2 score of 1 have an intermediate stroke risk and may or may not need an anticoagulant. In such cases, some cardiologists use the CHADS2-VASc scale, which adds ages 65 to 74, female sex, and history of vascular disease to the equation. With this, about a quarter of people with atrial fibrillation who have a CHADS2 score of 1 can be reclassified as at low risk of stroke. The other three-fourths would be reclassified as having a CHADS2 score of 2 or higher.
“If your CHADS2 score is 2 or greater, I think everybody agrees you should be on long-term anticoagulants,” Singer says.
Should you add an antiplatelet agent? “The most common reason to add an antiplatelet is when a patient has suffered a heart attack or unstable angina,” says Harvard’s Dr. Samuel Goldhaber, director of the Venous Thromboembolism Research Group at Brigham and Women’s Hospital. “Then, low-dose aspirin would be added. If the patient went on to get a stent, there would be a period of dual antiplatelet therapy.”
This is called triple therapy—an anticoagulant plus two antiplatelet drugs. But don’t be discouraged if your doctor prescribes this: triple therapy doesn’t have to last forever. Most doctors agree that patients who get a bare-metal stent to prop up a newly opened artery need triple therapy for only a month after the procedure, and those who get a stent that’s coated with drugs need triple therapy for three to six months. After that you can back down to a single antiplatelet agent, and you might go back to anticoagulant treatment alone a year after getting the stent.
Still, some people may have to stay on dual treatment for a long time. It’s a judgment call.
“If a patient just had a heart attack [without stent placement], it could be an extended period of time on both types of drug,” Goldhaber says.
Advice from the doctor …
What you can do to lower your bleeding risk
If you have atrial fibrillation and are taking an anticoagulant, you already should be doing what you can to lower your bleeding risk. But this becomes much more important if you’ve begun taking an antiplatelet drug, too.
Dr. Goldhaber offers this advice for minimizing bleeding risk:
It’s particularly important to take your medications exactly as your doctor prescribes. Ask your doctor about side effects you should watch for—especially gut discomfort that may signal bleeding inside the abdomen.