Colchicine and Fosaprepitant: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Fosaprepitant
Colchicine
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.
Fosaprepitant (Emend) is often given during chemotherapy to prevent nausea, and colchicine is used for gout and some other conditions. The concern here is that fosaprepitant can slow down the way your body breaks down colchicine. That means colchicine can build up to higher levels than intended, which raises the chance of side effects like stomach upset, diarrhea, muscle weakness, or more serious problems.
The good news is that your care team knows how to handle this. They may lower your colchicine dose or space it out and watch you more closely. Please don't change either medicine on your own, just check in with your pharmacist or doctor so they can tailor things safely for you.
Mechanism: Fosaprepitant (and its active form aprepitant) is a moderate CYP3A4 inhibitor. Colchicine is a CYP3A4 (and P-gp) substrate, so inhibition reduces its clearance and increases systemic exposure.
Effect/direction: Increased colchicine AUC/Cmax with heightened risk of dose-dependent toxicity (GI, myopathy, neuromuscular, myelosuppression). Colchicine has a narrow therapeutic index.
- Evidence: theoretical; magnitude not quantified.
- Onset: unspecified.
- Management: avoid combination where possible; if necessary, reduce colchicine daily dose or frequency and monitor closely for toxicity. Consider renal/hepatic impairment as added risk factors.
What happens
Increased colchicine exposure and an increased risk of colchicine-related toxicity
Interaction Deep Dive
Because of the risk of serious and potentially fatal toxicity, colchicine should not be taken together with CYP3A4 inhibitors. When such coadministration cannot be avoided, the colchicine regimen should be modified by lowering either the total daily amount or how often it is given, along with close observation for signs of colchicine toxicity1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of colchicine
How to manage this interaction
Both drugs can be used together when needed, but your care team will manage this carefully.
- Keep taking both as prescribed unless your doctor or pharmacist tells you otherwise.
- Your colchicine dose may need to be adjusted and individualized by your care team, either a lower daily dose or less frequent dosing while fosaprepitant is on board.
- Your team may monitor you more closely for signs of colchicine toxicity.
- Call your pharmacist or prescriber right away if you notice severe diarrhea, vomiting, muscle pain or weakness, numbness, or unusual tiredness.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Colchicine and Fosaprepitant together?
Fosaprepitant can raise colchicine levels and toxicity risk, so your care team may lower or space out your colchicine dose and watch you closely. Don't change either medicine yourself; check with your pharmacist or doctor. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colchicine and Fosaprepitant 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 is the Colchicine and Fosaprepitant interaction managed?
Both drugs can be used together when needed, but your care team will manage this carefully. Keep taking both as prescribed unless your doctor or pharmacist tells you otherwise. Your colchicine dose may need to be adjusted and individualized by your care team, either a lower daily dose or less frequent dosing while fosaprepitant is on board. Your team may monitor you more closely for signs of colch… Management is individual — always follow your own care team's guidance.
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 Colchicine or Fosaprepitant 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: MITIGARE(R) oral capsules, colchicine oral capsules. Hikma Specialty USA Inc (per FDA), Columbus, OH, 2024. DailyMed
Keep reading about Fosaprepitant
Keep reading about Colchicine
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist