What you carry at this position in your DNA and what research says about it.
Anticoagulant Bleeding Risk: 6/10 evidence, 10 publications.
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Sample genotype (not yours): C/C
Higher Bleeding Risk on Certain Blood Thinners
Slower metabolism of rivaroxaban and dabigatran may lead to higher drug levels in the body. This increases the risk of bleeding complications when taking these specific medications.
What this genotype means: Slower clearance of rivaroxaban; Increased risk of bleeding on dabigatran.
Sample genotype (not yours): C/T
Variable Bleeding Risk Depending on Anticoagulant Choice
Slower clearance of dabigatran may increase bleeding risk, while a lower risk of bleeding has been observed with apixaban. Response to rivaroxaban remains variable as clinical studies show conflicting results.
What this genotype means: Increased bleeding risk on dabigatran; Decreased bleeding risk on apixaban.
Sample genotype (not yours): T/T
Lower Bleeding Risk on Direct Oral Anticoagulants
Faster clearance of rivaroxaban and dabigatran helps maintain safer drug levels. This genotype is also associated with a lower risk of bleeding complications when taking apixaban.
What this genotype means: Faster metabolism of rivaroxaban; Lower bleeding risk on apixaban.
Gene function and biological role
Gene Function: The ABCB1 gene encodes P-glycoprotein, an essential ATP-dependent drug efflux pump located in the cell membrane [1]. This transporter plays a critical role in limiting the absorption and facilitating the elimination of various foreign substances and medications [1]. It is highly expressed in the intestines, liver, kidneys, and blood-brain barrier, where it pumps drugs out of cells and back into the bloodstream or excretory pathways [1]. Consequently, variations in this gene can significantly alter how the body processes and clears many commonly prescribed medications, including direct oral anticoagulants [2].
Variant Impact: Located within an intron of the ABCB1 gene, rs4148738 is a single nucleotide polymorphism that influences the expression or splicing of the P-glycoprotein transporter. This genetic change alters the rate at which certain direct oral anticoagulants are transported across cell membranes [3]. Clinical studies demonstrate that this variation affects the plasma concentrations and clearance rates of blood thinners like rivaroxaban and dabigatran [3] [4]. As a result, it has been linked to differences in the risk of bleeding complications during anticoagulant therapy [4].
Key Insight: This genetic variant specifically alters the safety profile of direct oral anticoagulants without changing their effectiveness in preventing blood clots.
Location: ABCB1. Chromosome 7 · 7q21.12 · 87.5 Mb
Estimated prevalence by population
Global 16.3%; European 20.4%; African 5.0%; East Asian 15.9%; South Asian 35.4%; Americas 15.7%; Ashkenazi 14.2%; Finnish 26.7%; Middle Eastern 18.3%; Amish 13.4%.
Estimated CC genotype frequency.
Global 45.2%; European 49.5%; African 34.8%; East Asian 47.9%; South Asian 48.2%; Americas 47.9%; Ashkenazi 47.0%; Finnish 49.9%; Middle Eastern 49.0%; Amish 46.4%.
Estimated CT genotype frequency.
Global 38.6%; European 30.0%; African 60.2%; East Asian 36.2%; South Asian 16.4%; Americas 36.4%; Ashkenazi 38.8%; Finnish 23.3%; Middle Eastern 32.7%; Amish 40.2%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Pharmacogenomics
Anticoagulant & Blood Thinner Response
Rivaroxaban Response. Evidence: 6/10. Source: PMID 39459499. Slower Metabolism.
Dabigatran Response. Evidence: 5/10. Source: PMID 38525959. Increased Bleeding.
Apixaban Response. Evidence: 5/10. Source: PMID 34043814. Typical Response.
Showing effects for C/T genotype
Rivaroxaban Response. Evidence: 6/10. Source: PMID 39459499. Variable Response.
Apixaban Response. Evidence: 5/10. Source: PMID 34043814. Lower Bleeding Risk.
Showing effects for T/T genotype
Rivaroxaban Response. Evidence: 6/10. Source: PMID 39459499. Faster Metabolism.
Dabigatran Response. Evidence: 5/10. Source: PMID 38525959. Typical Response.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Processing of certain direct oral anticoagulants is significantly slower in individuals with this genotype. Clinical research indicates that this slower clearance leads to higher plasma concentrations of medications like rivaroxaban [1]. Consequently, there is an elevated risk of experiencing bleeding complications, such as gastrointestinal or minor hemorrhages, during therapy [1]. Similar patterns of increased bleeding risk have been observed in patients treated with dabigatran [2]. These findings suggest that standard dosing of these specific blood thinners might result in higher-than-expected drug exposure [1] [2]. However, this genetic variation does not appear to affect the risk of blood clots or stroke itself [2].
Slower clearance of rivaroxaban; Increased risk of bleeding on dabigatran.
Sample genotype: CT (Heterozygous)
Metabolism of direct oral anticoagulants shows a complex, drug-specific pattern with this heterozygous genotype. Clinical studies on dabigatran therapy show a trend toward slower drug clearance and an increased likelihood of bleeding complications [1]. Conversely, research on apixaban indicates a protective effect, with carriers experiencing a decreased risk of bleeding events [2]. Studies on rivaroxaban metabolism remain inconsistent, with some showing faster clearance and others showing slower clearance [3]. These contrasting drug-specific effects highlight the importance of the specific anticoagulant chosen for therapy [1] [2].
Increased bleeding risk on dabigatran; Decreased bleeding risk on apixaban.
Sample genotype: TT (Homozygous)
Efficient clearance of direct oral anticoagulants is a key feature associated with this genotype. Clinical evidence shows that carrying two copies of the major T allele promotes faster metabolism of rivaroxaban, reducing the likelihood of drug accumulation [1]. Studies also indicate a significantly lower risk of bleeding complications during apixaban therapy compared to other genotypes [2]. Furthermore, this genotype avoids the elevated bleeding risks associated with dabigatran that are seen in carriers of the C allele [3]. These combined factors contribute to a more stable and safer profile when undergoing standard anticoagulant therapy [1] [2] [3].
Faster metabolism of rivaroxaban; Lower bleeding risk on apixaban.
Variants with shared genetic architecture
rs1045642 · ABCB1 Gene · Chr 7 · Medication Response
rs2032582 · ABCB1 Gene · Chr 7 · Lung Cancer Risk
rs1128503 · ABCB1 Gene · Chr 7 · Medication Response
Pharmacogenetics of dabigatran etexilate interindividual variability.
Pharmacogenetics of Bleeding and Thromboembolic Events in Direct Oral Anticoagulant Users.
Content updated August 2026.
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