Doxifluridine and Gemcitabine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Gemcitabine
Doxifluridine
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
Enhanced fluorouracil systemic exposure and possible toxicity
Interaction Deep Dive
A significant increase in systemic fluorouracil exposure occurs when gemcitabine is coadministered. This may be useful in maximizing the antitumor effects and reduce the occurrence of side effects of fluorouracil1.
Why it happens (mechanism)
Unknown
Literature reports
1 report — tap to read
a) Gemcitabine enhances systemic exposure to fluorouracil in cancer patients. Twenty patients with advanced gastroenteric carcinoma were included in the experimental group and received gemcitabine and folinic acid (FUFA). Sixteen patients with gastroenteric carcinoma were included in the control group and received FUFA therapy. Patients in the experimental group had a higher fluorouracil area under the concentration-time curve (AUC), plasma half-life, lower mean total clearance, and volume of distribution. The fluorouracil AUC in patients taking gemcitabine and FUFA was 555 +/- 209 mcg/mL/min and in patients taking FUFA 244 +/- 89 (p less than 0.001). The author suggests that the results of this study should be taken into account when designing clinical trials testing gemcitabine and fluorouracil in combination in order to maximize the antitumor effects and reduce the occurrence of side effects 1.
Common questions
Can I take Doxifluridine and Gemcitabine together?
Enhanced fluorouracil systemic exposure and possible toxicity Always confirm with your pharmacist or prescriber before making any change.
How serious is the Doxifluridine and Gemcitabine interaction?
It is rated minor. Usually limited clinical impact.
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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Doxifluridine or Gemcitabine 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 anything you'd monitor while I'm on both?
References (1)
- Correale P, Cerretani D, Marsili S, et al: Gemcitabine increases systemic 5-fluorouracil exposure in advanced cancer patients. Eur J Cancer 2003; 39:1547-1551. PubMed
Keep reading about Gemcitabine
Keep reading about Doxifluridine
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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