Defibrotide and Dalteparin Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Dalteparin Injection
Defibrotide
No brand names on record
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
Increased risk of bleeding
Interaction Deep Dive
Concomitant use of defibrotide and a systemic antithrombotic agent such as this drug is contraindicated as the pharmacodynamic activity of the antithrombotic agent may be enhanced, leading to an increased risk of bleeding. This does not include routine use for maintenance or reopening of central venous lines. Discontinue antithrombotic agents prior to initiating therapy with defibrotide, and consider delaying initiation of defibrotide until effects of this drug have subsided1.
Why it happens (mechanism)
Enhanced pharmacodynamic activity of antithrombotic agent
Common questions
Can I take Defibrotide and Dalteparin Injection together?
Increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.
How serious is the Defibrotide and Dalteparin Injection interaction?
It is rated contraindicated. These should generally not be used together.
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.
Questions for your pharmacist
- Does my dose of Defibrotide or Dalteparin Injection 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 (1)
- Product Information: DEFITELIO(R) intravenous injection, defibrotide sodium intravenous injection. Jazz Pharmaceuticals (per FDA), Palo Alto, CA, 2016. DailyMed
Keep reading about Dalteparin Injection
Keep reading about Defibrotide
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