Colchicine and Vandetanib: 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
Vandetanib
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.
Vandetanib can cause colchicine to build up in your body. Colchicine is normally pumped out of your cells by a transporter called P-gp. Vandetanib slows that pump down, so more colchicine stays in your system than it should. Because colchicine is a strong drug, having too much can lead to serious problems like severe diarrhea, muscle weakness, and dangerous effects on your blood and organs.
This is considered a very serious combination, so please do not start, stop, or change either medicine on your own. Talk with your pharmacist or doctor. They can review your kidney and liver health and decide the safest plan for you.
Effect: Vandetanib inhibits P-gp-mediated efflux of colchicine, increasing colchicine exposure and the risk of life-threatening toxicity. Neither drug is a prodrug; this is a direct pharmacokinetic increase in the affected drug (colchicine).
- Direction: Increased colchicine exposure (higher AUC/Cmax).
- Severity: Contraindicated per labeling for colchicine with P-gp inhibitors.
- Evidence: Theoretical (extrapolated from documented fatal toxicity with P-gp/CYP3A4 inhibitors).
- Management: Avoid in renal or hepatic impairment. In normal organ function, if unavoidable, reduce colchicine daily dose or frequency and monitor closely for toxicity (GI, myopathy, myelosuppression).
What happens
Increased colchicine exposure and an increased risk of colchicine toxicity
Interaction Deep Dive
Both CYP3A4 and P-gp act on colchicine as a substrate. Cases of toxicity have been documented when colchicine was given together with clarithromycin, which inhibits both CYP3A4 and P-gp. Toxic effects have likewise been seen when colchicine was combined with a CYP3A4 inhibitor and when colchicine was combined with a P-gp inhibitor3. Using colchicine alongside P-gp inhibitors is contraindicated, since life-threatening and fatal colchicine toxicity has occurred in such patients even when colchicine was taken at therapeutic doses 1. This combination is likewise contraindicated in individuals with renal or hepatic impairment, because life-threatening and fatal drug interactions have been reported. For patients whose renal and hepatic function is normal 2, when colchicine must be given together with a P-gp inhibitor, modify the colchicine dose by lowering either the total daily amount or how often it is taken. Watch carefully for signs of colchicine toxicity 3.
Why it happens (mechanism)
Inhibition of P-gp-mediated colchicine efflux transport
How to manage this interaction
This combination is generally avoided. The most important step is to let your care team know you take both, since they may choose a different medication or adjust things.
- Keep taking both exactly as prescribed until your prescriber or pharmacist tells you otherwise.
- If both are truly needed and your kidneys and liver work normally, your team may lower your colchicine dose or how often you take it, and monitor you more closely.
- This combination is avoided entirely if you have kidney or liver problems.
- Report warning signs promptly: severe diarrhea, vomiting, muscle weakness or pain, numbness, or unusual bruising or infections.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Colchicine and Vandetanib together?
Vandetanib can raise colchicine to dangerous levels by blocking its P-gp transporter, and this pairing is contraindicated, so contact your pharmacist or doctor before taking them together. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colchicine and Vandetanib 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 is the Colchicine and Vandetanib interaction managed?
This combination is generally avoided. The most important step is to let your care team know you take both, since they may choose a different medication or adjust things. Keep taking both exactly as prescribed until your prescriber or pharmacist tells you otherwise. If both are truly needed and your kidneys and liver work normally, your team may lower your colchicine dose or how often you take it,… 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 Vandetanib 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 (3)
- Product Information: LODOCO(R) oral tablets, colchicine oral tablets. AGEPHA Pharma USA, LLC (per FDA), Parsippany, NJ, 2023. DailyMed
- Product Information: COLCRYS oral tablets, colchicine oral tablets. Takeda Pharmaceuticals America Inc (per FDA), Deerfield, IL, 2020. DailyMed
- Product Information: GLOPERBA(R) oral solution, colchicine oral solution. Romeg Therapeutics LLC (per FDA), Woburn, MA, 2019. DailyMed
Keep reading about Vandetanib
Keep reading about Colchicine
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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:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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