[Hereditary warfarin resistance].

Area of Science:

• Pharmacogenomics
• Clinical Pharmacology

Background:

• Warfarin is a primary oral anticoagulant in Norway, with dosage individualized based on International Normalized Ratio (INR) monitoring.
• A rare genetic condition, hereditary warfarin resistance, leads to exceptionally high warfarin dosage requirements.

Observation:

• This study details two brothers exhibiting significantly reduced sensitivity to warfarin therapy.
• Both patients required substantial daily warfarin doses (25-35 mg) to achieve therapeutic INR levels.

Findings:

• Hereditary warfarin resistance is a rare genetic cause of diminished warfarin sensitivity.
• Despite high doses, patients with this condition do not present an elevated risk of thromboembolism.

Implications:

• Understanding hereditary warfarin resistance is crucial for accurate anticoagulation management in affected individuals.
• This condition highlights the importance of pharmacogenetic considerations in drug therapy.