The Medical Letter on Drugs and Therapeutics
Pharmacogenetic-Based Dosing of Warfarin
Subscribers: Log in to read full article.  Not a subscriber?  Subscribe or purchase article.
Revised 6/9/08: Table 1: Acetaminophen (Tylenol*) was added.

Warfarin sodium (Coumadin, and others) and other coumarin anticoagulants prevent thrombosis, but patient response is highly variable and overanticoagulation can lead to hemorrhage.1 Genotyping patients for single nucleotide polymorphisms (SNPs) that affect coumarin metabolism and sensitivity may help clinicians estimate the therapeutic warfarin dose. The FDA has added a note to warfarin labeling recommending lowrange doses for patients with such genetic variations. Commercial tests for these variants are now available and cost about $500 per test.

CLINICAL DOSING — Traditionally, warfarin has been dosed empirically, with the initial dose based on the indication and perhaps the weight and age of the patient. By adjusting the dose based on the International Normalized Ratio (INR) response, clinicians eventually arrive at the therapeutic dose. ... more      

The Medical Letter is a subscriber-funded nonprofit organization that publishes critical appraisals of new prescription drugs and comparative reviews of drugs for common diseases.

Would you like to read the rest of this article?  Gain access below.

Subscriptions to The Medical Letter on Drugs and Therapeutics include:
  • Print version published and mailed biweekly (26 issues/year)
  • Unlimited online access to current and past issues (1988 - present)
  • Mobile App for iOS, Android, and Kindle Fire
  • FREE online per issue CME/CE
Purchase this article:
Title: Pharmacogenetic-Based Dosing of Warfarin
Article code: 1286b
 Electronic, downloadable article - $45
Gain access through your organization
Ask your librarian to consider an Institutional Subscription to The Medical Letter.
Recommend to your librarian