Paroxetine and Betrixaban: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Paroxetine
Betrixaban
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
An increased risk of bleeding
Interaction Deep Dive
Case-control and cohort studies have shown that the combined use of SSRIs and anticoagulants has been associated with an increased risk of bleeding12. Bleeding events reported have included epistaxis, ecchymosis, hematoma, petechiae, and life-threatening hemorrhages. Altered anticoagulant effects (including increased bleeding) have been reported with the coadministration of SSRIs with warfarin 24. If PARoxetine and an anticoagulant are coadministered, monitor patients for signs of increased bleeding 3.
Why it happens (mechanism)
Release of serotonin by platelets; additive effects on hemostasis
Literature reports
4 reports — tap to read
a) According to a retrospective cohort study (n=234), there was an increased risk of clinically relevant bleeding (hospital admission due to bleeding) in patients receiving warfarin for atrial fibrillation during concomitant SSRI therapy or within 2 weeks following SSRI therapy termination. Patients with a mean age of 72 +/- 7 years receiving warfarin plus SSRI (n=117) were matched with randomly selected patients who received warfarin only (n=117). SSRI included FLUoxetine, citalopram, PARoxetine, sertraline, fluvoxaMINE, or escitalopram. Nine patients experienced 11 bleeding episodes during 213.9 treatment years in the warfarin plus SSRI group, and 10 patients experienced 14 bleedings during 586.4 treatment years in the warfarin-only group. The corresponding total incidences of bleedings were 51.4 and 23.9 per 1000 treatment years, respectively. The hazard ratio for first bleedings during treatment with warfarin plus SSRI was 3.49 (95% CI; 1.37 to 8.91) compared with warfarin only. The SSRI implicated in patients experiencing bleeding at the time of concomitant administration were sertraline or citalopram. The addition of an SSRI was not associated with a change in warfarin dose or INR. The results of the study may be limited by earlier bleeding events, unknown patient adherence, and exclusion of clopidogrel, dipyridamol, corticosteroids and anticoagulants other than warfarin in the model 1.
b) A population-based, case-controlled study of new coumarin users (acenocoumarol and phenprocoumon) with concomitant selective serotonin reuptake inhibitors (SSRIs) resulted in an increased risk of hospitalization due to non-gastrointestinal bleeding. Using national pharmacy and hospitalization records, Netherlands researchers identified 1848 cases that were admitted for abnormal bleeding and compared them with 5818 control subjects also taking coumarins. Median duration of treatment in patients was 220 days (range, 1 to 4690 days). Patients on SSRIs showed greater risk for hospitalization for non-gastrointestinal bleeding (adjusted odds ratio (OR) 1.7, 95% confidence interval (CI), 1.1 to 2.5), however, the rate of gastrointestinal bleeding (adjusted OR 0.8, 95% CI, 0.4 to 1.5) was not significantly different 2.
c) Preliminary data suggest that there may be a pharmacodynamic interaction (that causes an increased bleeding diathesis with unaltered prothrombin time) between PARoxetine and warfarin 5.
d) In a multiple-dose study, several days of combined therapy with warfarin and PARoxetine resulted in mild but clinically significant bleeding in 5 of 27 subjects. This effect occurred in the absence of a significant enhancement in warfarin-induced hypoprothrombinemia or changes in either PARoxetine or warfarin disposition 6.
Common questions
Can I take Paroxetine and Betrixaban together?
An increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.
How serious is the Paroxetine and Betrixaban interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Paroxetine or Betrixaban need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (6)
- Wallerstedt SM, Gleerup H, Sundstrom A, et al: Risk of clinically relevant bleeding in warfarin-treated patients-influence of SSRI treatment. Pharmacoepidemiol Drug Saf 2009; 18(5):412-416. PubMed
- Schalekamp T, Klungel OH, Souverein PC, et al: Increased bleeding risk with concurrent use of selective serotonin reuptake inhibitors and coumarins. Arch Intern Med 2008; 168(2):180-185. DOI
- Product Information: PEXEVA(R) oral tablets, paroxetine mesylate oral tablets. Sebela Pharmaceuticals Inc (per FDA), Roswell, GA, 2023.
- Product Information: PAXIL(R) oral tablets, oral suspension, paroxetine oral tablets, oral suspension. Apotex Corp (per FDA), Weston, FL, 2023. DailyMed
- Product Information: BRISDELLE(R) oral capsules, paroxetine oral capsules. Sebela Pharmaceuticals Inc (per FDA), Roswell, GA, 2023. DailyMed
- Bannister SJ, Houser VP, Hulse JD, et al: Evaluation of the potential for interactions of paroxetine with diazepam, cimetidine, warfarin, and digoxin. Acta Psychiatr Scand 1989; 80(suppl 350):102-106. PubMed
Keep reading about Paroxetine
Keep reading about Betrixaban
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
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