DOAC Dosing and Adherence in AFib: Barriers to Staying on Therapy

This episode, "DOAC Dosing and Adherence in AFib: Barriers to Staying on Therapy," finds Dr. Barnes walking through the practical details of prescribing DOACs.

Dr. Barnes walks through the four DOACs currently available in the United States and their dosing. Apixaban is the most widely prescribed, at five milligrams twice daily. The dose drops to 2.5 milligrams twice daily when a patient has two or more of three criteria: age over 80, weight under 60 kilograms, or serum creatinine above 1.5.

Rivaroxaban is dosed at 20 milligrams once daily. It is reduced to 15 milligrams when creatinine clearance falls below 50. Dabigatran, the first DOAC on the market, is far less common. Its standard dose is 150 milligrams twice daily, cut to 75 milligrams if creatinine clearance is below 30.

Edoxaban is probably the least used. It is dosed at 60 milligrams once daily and halved to 30 milligrams when creatinine clearance is below 50. It also carries a warning against use when creatinine clearance exceeds 95.

Dr. Barnes notes that four drugs with four dosing schemes can confuse prescribers. Two drugs are dosed twice daily and two once daily, and that difference matters to patients. Some tell him they cannot remember a twice-daily drug, so a once-daily option may fit better. Others are comfortable with twice-daily dosing, and then coverage and tolerability become the priority.

He identifies adherence as a major concern. Only about two thirds of patients demonstrate good adherence to oral anticoagulants at one year. Patients stop for several reasons, including cost, uncertainty about why they take it, or side effects such as bleeding. Discontinuation at one year ranges from roughly 25 to 40 percent.

Dr. Barnes frames the clinician's task as three steps. Choose the right drug and dose, work with the patient on taking it as prescribed, and help the patient stay on it so they realize the benefit.

Our next episode, "Generic DOACs in AFib: What Lower Costs Could Mean for Patients," turns to how generic versions may change cost conversations.