New guidance supports short-term dual antiplatelet therapy

A new practice guideline published in BMJ strongly recommends starting dual antiplatelet therapy with aspirin and clopidogrel within 24 hours of a high-risk transient ischemic attack (TIA) or minor stroke and continuing this therapy for 10 to 21 days before switching to single antiplatelet therapy.

This practice has not been broadly adopted, with many clinicians continuing to use a single antiplatelet agent at the onset of an event. Reasons for the new guideline include data that do not support the benefits of dual antiplatelet therapy when used long term and dual therapy being considered too risky after a major stroke.

“Dual antiplatelet therapy following acute stroke has been controversial,” said Zachary Noel, PharmD, BCPS, assistant professor of pharmacy practice and science at the University of Maryland School of Pharmacy. “Recently, as referenced in the BMJ guideline, new data have given us insight on when to administer dual antiplatelet therapy and for how long,” said Noel.

“The key takeaway point is that for high-risk TIA or minor stroke, dual antiplatelet therapy with aspirin and clopidogrel for 21 days is reasonable. Extending dual antiplatelet therapy beyond 21 days produces little to no additional benefit; thus only a single antiplatelet should be continued after 21 days.”

Noel said it is also worth noting that patients who experience a cardioembolic stroke (e.g., secondary to atrial fibrillation [AF]) should receive anticoagulation, not antiplatelet, therapy. Patients with major stroke should receive single antiplatelet therapy because of the risk of hemorrhagic conversion with dual antiplatelet therapy.

Three trials (FASTER, CHANCE, POINT) involving 10,447 participants with a high-risk TIA or minor stroke event support the current recommendation for dual antiplatelet therapy. A systematic review and meta-analysis found that when aspirin monotherapy was compared with dual antiplatelet therapy with clopidogrel and aspirin started within 24 hours of symptom onset, dual therapy significantly reduced the risk of nonfatal recurrent stroke. Dual antiplatelet therapy led to small improvements in functional disability and quality of life but was also associated with a small increase in moderate or major extracranial bleeding.

According to the authors of the review, “Dual antiplatelet therapy with clopidogrel and aspirin given within 24 hours after high-risk TIA or minor ischemic stroke reduces subsequent stroke by about 20 in 1,000 population, with a possible increase in moderate to severe bleeding of 2 per 1,000 population. Discontinuation of dual antiplatelet therapy within 21 days, and possibly as early as 10 days, of initiation is likely to maximize benefit and minimize harms.”

For the full article, please visit www.pharmacytoday.org for the March 2019 issue of Pharmacy Today.