Improved Stability in INR with Coumadin for a Patient Requiring Very Low Warfarin Doses
Journal of Pharmacy Technology
Objective: To describe a patient who required very low doses of warfarin but who could not achieve therapeutically stable anticoagulation until treatment was switched from generic to branded warfarin.
Case Summary: A 53-year-old male with a history of hypertension, coronary artery disease, heart failure, and mild renal insufficiency was diagnosed with atrial fibrillation during a routine examination. Anticoagulation was started with warfarin 5 mg daily. The patient presented to the anticoagulation clinic 2 days later with an international normalized ratio (INR) of 5.4 and no signs or symptoms of bleeding. Warfarin was held for 3 days until the INR was
Discussion: Many patients are able to take generic warfarin without problems. However, case reports have documented occasional patients who have had problems after switching to a generic product. Large cohorts have been switched to generic warfarin without experiencing significant changes in therapeutic control. However, 1 cohort study found that patients who required very low warfarin dosages had significant changes in their INR after switching to a generic product.
Conclusions: Patients who require very low warfarin dosages to consistently maintain therapeutic anticoagulation may experience less therapeutic stability while on a generic product.
Warfarin, anticoagulation, couamdin
Anderson, Douglas C.; Poulos, P.; and Scoggins, B. P., "Improved Stability in INR with Coumadin for a Patient Requiring Very Low Warfarin Doses" (2010). Pharmacy Practice Faculty Publications. 152.