Dosing Considerations for Anticoagulant Therapy in the Elderly

Introduction to Dosing Adjustments

The European Society of Cardiology recommends that for patients over 65 years old, the dose of direct oral anticoagulants (DOACs) such as dabigatran (Pradaxa) should be reduced due to age-related decline in renal function and increased risk of bleeding 1, 2
For patients over 65, consideration should be given to reducing the dose of anticoagulant medications due to age-related decline in renal function 2

Renal function decline - creatinine clearance decreases with age 2, 5
Increased risk of gastrointestinal and intracranial bleeding in older adults 1, 2
Dabigatran (Pradaxa) and rivaroxaban: increased risk of gastrointestinal bleeding compared to warfarin in patients over 75 with atrial fibrillation or venous thromboembolism 2

Periodic monitoring of renal (and hepatic) function is recommended in older adults taking DOACs 2
Dabigatran (Pradaxa) should be avoided if creatinine clearance is less than 30 mL/min/1.73 m^2 2
Caution should be exercised when using dabigatran and rivaroxaban in patients over 75 with atrial fibrillation or venous thromboembolism 2
In older adults, there is a high prevalence of inappropriate dosing of DOACs, with underdosing being the most common form and occurring in 4.7% to 26.1% of patients 1

Children weighing over 40 kg should receive adult doses, regardless of age 6, 7, 8

"Blind" continuation of home dosing and incorrect prescription dosing are common causes of overdosing 1
Complexity and variability in dose reduction criteria for each specific DOAC may play a role in variability between medications 1
Advanced age, low body weight, and high serum creatinine are predictive and rational factors for both underdosing and overdosing 1