In the near future, a new generation of easy-to-use blood-thinning drugs will probably substitute Coumadin for patients with irregular heartbeats who are at risk for stroke, states a journal article by Loyola University Medical Center physicians.
Unlike Coumadin, the new drugs do not require patients to come in to the clinic on a regular basis to check the dose. Nor do the drugs require extensive dietary restrictions.
First author Sarkis Morales-Vidal, MD, and colleagues describe the new drugs in a review article in the February issue of the journal Expert Reviews. Co-authors are Michael J. Schneck, MD, Murray Flaster, MD, and José Biller, MD. All are in the Department of Neurology, Stroke Program, of Loyola University Chicago Stritch School of Medicine. Biller is department chair.
Atrial fibrillation is the most common form of irregular heartbeat, and a major cause of stroke in the elderly. Electrical signals, which regulate the heartbeat, become erratic. Instead of beating regularly, the upper chambers of the heart quiver. Not all the blood gets pumped out, so clots can form. The clots can migrate to the brain and cause strokes.
More than 3 million Americans have atrial fibrillation, and the number is increasing, due in part to the aging population.
Coumadin's generic name is warfarin. For more than 30 years, the drug had been the only anticoagulant for primary and secondary stroke prevention in patients with atrial fibrillation. But the Food and Drug Administration recently approved dabigatran and rivaroxaban to reduce the risk of stroke and blood clots in patients with atrial fibrillation that is not caused by a heart valve problem. The FDA is considering an application to approve apixaban for the same use.
Coumadin must be carefully monitored. If the dose is too high, a patient could experience excessive bruising and be at higher risk for brain hemorrhages. If the dose is too low, the drug would be ineffective in preventing blood clots. Patients typically must come in at least once a month for a blood test to determine whether the dose needs to be adjusted. Some patients have to come in as often as twice a week.
Coumadin patients also must restrict their diets. For example, they should consume only small amounts of cranberry juice and alcohol and not eat large amounts of foods that are rich in vitamin K, such as spinach, brussels sprouts and green tea.
Disadvantages of the new medications include the limited clinical experience and lack of antidotes, the researchers wrote. The newer drugs are more expensive than Coumadin, but reduce the cost of patient monitoring and blood testing, Morales said.
Dabigatran is an effective alternative to Coumadin for stroke prevention in patients with non-valvular atrial fibrillation. Rivaroxaban is another promising alternative for those patients. Apixaban appears to be better than aspirin for stroke prevention in atrial fibrillation patients who are not candidates for Coumadin therapy, Morales and colleagues wrote.
The authors predict that within the next few years, the new drugs will likely replace Coumadin for long-term anticoagulation in selective patients with non-valvular atrial fibrillation.