Fluvoxamine and Betrixaban: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Fluvoxamine
No brand names on recordBetrixaban
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
The release of serotonin by platelets is important for maintaining hemostasis. Case-control and cohort studies have shown that the combined use of SSRIs and anticoagulants has been associated with an increased risk of bleeding231. 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. In patients receiving warfarin and fluvoxaMINE concomitantly for 2 weeks, warfarin plasma concentrations increased by 98% and prothrombin times were prolonged. FluvoxaMINE appears to inhibit several cytochrome P450 isoenzymes which may include CYP1A2 and CYP2C9 isozymes, which are responsible for warfarin metabolism 41.
Why it happens (mechanism)
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, p=0.009) 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 (p=0.48 and p=0.31 respectively). 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 3.
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 4.
c) A hospitalized 80-year-old female was started on intravenous heparin and oral warfarin therapy due to an embolic stroke secondary to atrial fibrillation and mitral stenosis. Her warfarin dose was maintained at 1 mg daily, with her INR between 2.5 and 3. FluvoxaMINE 25 mg daily was started for depression, and her warfarin dose was increased to 1.5 mg daily 3 days later due to worsening of the left hemiparesis. Three days later, her INR was 9.96, and a repeat INR to rule out laboratory error was 11.3. Warfarin was discontinued, fresh frozen plasma was given, and fluvoxaMINE was discontinued. Six days later, warfarin was again started at 1 mg daily, and the INR increased over 4 days to 11.8. The elevated INR was attributed to the persisting effect of fluvoxaMINE. She was eventually stabilized on warfarin 1 mg daily with INR values between 2 and 2.5 5.
d) When fluvoxaMINE maleate (50 mg thrice daily) was administered concomitantly with warfarin for two weeks, warfarin plasma concentrations increased by 98% and prothrombin times were prolonged 2.
Common questions
Can I take Fluvoxamine and Betrixaban together?
An increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.
How serious is the Fluvoxamine 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 "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Fluvoxamine 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 (5)
- Product Information: LUVOX(R) CR extended-release oral capsules, fluvoxamine maleate extended-release oral capsules. Jazz Pharmaceuticals,Inc, Palo Alto, CA, 2008. DailyMed
- Product Information: Fluvoxamine maleate oral tablets, fluvoxamine maleate oral tablets. ANI Pharmaceuticals Inc (per FDA), Baudette, MN, 2023. DailyMed
- 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
- Yap KB & Low ST: Interaction of fluvoxamine with warfarin in an elderly woman. Singapore Med J 1999; 40:480-482.
Keep reading about Fluvoxamine
Keep reading about Betrixaban
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