Related Experiment Video

Updated: May 7, 2026

Rapid Point-of-Care Assay of Enoxaparin Anticoagulant Efficacy in Whole Blood
11:17

Rapid Point-of-Care Assay of Enoxaparin Anticoagulant Efficacy in Whole Blood

Published on: October 12, 2012

Impact of genotype-guided dosing on anticoagulation visits for adults starting warfarin: a randomized controlled

Daniel E Jonas1, James P Evans, Howard L McLeod

  • 1Department of Medicine, University of North Carolina at Chapel Hill School of Medicine, 5034 Old Clinic Building, CB #7110, Chapel Hill, NC 27599, USA.

Pharmacogenomics
|October 4, 2013
PubMed

Insights

Genotype-guided warfarin dosing did not significantly improve anticoagulation visits or time in therapeutic range (TTR). The study lacked power to detect smaller differences in outcomes for warfarin therapy.

Area of Science:

  • Pharmacogenomics
  • Clinical Pharmacology

Background:

  • Warfarin dosing is complex, influenced by genetic factors like VKORC1 and CYP2C9.
  • Personalized dosing strategies aim to optimize warfarin therapy and reduce adverse events.

Purpose of the Study:

  • To evaluate the efficacy of genotype-guided warfarin dosing compared to standard clinical dosing.
  • To assess the impact of genetic information on anticoagulation control and clinical outcomes.

Main Methods:

  • A randomized controlled trial involving 109 adults.
  • Participants received warfarin dosing based on either genetic (VKORC1, CYP2C9) plus clinical factors or clinical factors alone.
  • Primary outcomes included anticoagulation visits and time in therapeutic range (TTR) over 90 days.

Main Results:

  • No significant difference was observed in the number of anticoagulation visits (6.96 vs 6.37) or TTR (0.40 vs 0.43) between the groups.
  • Trends favored the genotype-guided group for fewer emergency visits, hospitalizations, major bleeding, thrombotic events, and deaths, but these were not statistically significant.

Conclusions:

  • Genotype-guided warfarin dosing did not demonstrate a significant benefit in reducing anticoagulation visits or improving TTR in this study.
  • The trial was underpowered to detect smaller differences in utilization and health outcomes, suggesting larger trials may be needed.
Abstract

Related Concept Videos

Anticoagulant Drugs: Vitamin K Antagonists and Direct Oral Anticoagulants01:18

Anticoagulant Drugs: Vitamin K Antagonists and Direct Oral Anticoagulants

Oral anticoagulants are vital tools in preventing and treating blood clotting disorders. This diverse class of medications can be categorized as vitamin K antagonists, exemplified by warfarin, and direct thrombin inhibitors (DTIs), such as dabigatran, as well as factor Xa inhibitors, including rivaroxaban.
Warfarin, a prominent vitamin K antagonist family member, exerts its effect by inhibiting the enzyme VKORC1 (vitamin K epoxide reductase complex 1). By hindering this enzyme, warfarin...
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu01:29

Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu

Genetic variations significantly influence drug response through pharmacokinetics, receptor interactions, and biologic milieu modifications. Pharmacokinetic alterations impact drug metabolism and clearance, affecting efficacy and toxicity. Variants in drug-metabolizing enzymes, such as CYP2C9 and CYP2C19, alter drug activation and elimination. For example, CYP2C9 loss-of-function variants require lower warfarin doses to prevent excessive bleeding, while CYP2C19 variants reduce clopidogrel...
Venous Thrombosis III: Interprofessional Care01:29

Venous Thrombosis III: Interprofessional Care

Venous thrombosis requires effective prevention and treatment strategies to improve patient outcomes and reduce potential complications.Prevention StrategiesHealthcare providers must prioritize preventing venous thromboembolism (VTE) for all adult patients upon admission. Interventions depend on bleeding and thrombosis risk, medical history, current medications, diagnoses, planned procedures, and patient preferences. Patients on bed rest should change positions every two hours and, if not...
Pharmacogenetics of Drug Metabolism: Overview01:27

Pharmacogenetics of Drug Metabolism: Overview

Genetic polymorphism in drug metabolism is crucial to the inter-individual variability observed in drug responses. Drug metabolism primarily involves the chemical modification of drugs and other xenobiotics to enhance their elimination by increasing their polarity. Two main classes of enzymes mediate this biotransformation process: Phase I enzymes, primarily cytochrome P450s, catalyze oxidation and reduction reactions, while other enzymes, such as esterases, mediate hydrolysis, and Phase II...
Dosage Regimens: Designs and Approaches01:28

Dosage Regimens: Designs and Approaches

Designing a dosage regimen, which refers to the manner of drug administration, is a complex process involving the selection of drug dose, route, and frequency. This process is underpinned by pharmacokinetic parameters derived from tests and population averages. These parameters are then tailored to patient-specific variables such as diagnosis, demographics, and allergy status. Once therapy commences, therapeutic response monitoring is critical and achieved through clinical and physical...
Anticoagulant Drugs: Low-Molecular-Weight Heparins01:30

Anticoagulant Drugs: Low-Molecular-Weight Heparins

Hemostasis is a crucial process that prevents excessive blood loss from damaged blood vessels. It involves various mechanisms such as vasoconstriction, platelet adhesion and activation, and fibrin formation. The importance of each mechanism depends on the type of vessel injury. In contrast, thrombosis is the abnormal formation of a blood clot within the blood vessels, leading to potential complications if the clot obstructs blood flow. Thrombosis can be caused by increased coagulability of the...