Idelalisib and Colchicine: 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
Idelalisib
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.
Idelalisib (Zydelig) strongly blocks a liver enzyme called CYP3A4, which is the same enzyme your body uses to break down colchicine. When that enzyme is blocked, colchicine can build up to dangerous levels. This matters a lot because colchicine has a very narrow safety window, and too much of it has caused serious, even fatal, poisoning, with problems like severe diarrhea, muscle weakness, and blood cell and organ damage.
The good news is your care team knows how to handle this. Please do not stop or change either medicine on your own. Talk with your pharmacist or doctor, who can lower your colchicine dose, space it out, or watch you closely so you stay safe.
Mechanism: Idelalisib is a strong CYP3A4 inhibitor; colchicine is a CYP3A4 (and P-gp) substrate. Inhibition reduces colchicine clearance, increasing exposure (AUC/Cmax) and the risk of life-threatening toxicity. Colchicine is a narrow-therapeutic-index drug.
- Direction: increased colchicine effect/toxicity
- Severity: contraindicated, especially with renal or hepatic impairment
- Evidence: probable; fatal toxicity reported at therapeutic doses
Management: Contraindicated in renal/hepatic impairment. In normal function, reduce colchicine dose or frequency (e.g., gout flare: 0.6 mg once, then 0.3 mg 1 hr later, no repeat before 3 days; prophylaxis: 0.6 mg BID to 0.3 mg daily; FMF max 0.6 mg/day). Monitor closely for toxicity (GI, myelosuppression, neuromuscular).
What happens
Increased colchicine exposure and an increased risk of fatal toxicity
Interaction Deep Dive
Colchicine should not be combined with strong CYP3A4 inhibitors, since therapeutic doses of colchicine in such patients have been associated with reports of life-threatening and fatal colchicine toxicity1. When patients have renal or hepatic impairment, the combination of colchicine with strong CYP3A4 inhibitors (which include every protease inhibitor other than fosamprenavir) is contraindicated. For patients whose renal and hepatic function is normal and who are taking a strong CYP3A4 inhibitor concurrently, or who received one within the preceding 14 days, the colchicine dose must be modified. When managing a gout flare, lower the colchicine dose to a single 0.6 mg tablet followed one hour later by 0.3 mg, and do not repeat this dose sooner than 3 days. For gout flare prophylaxis, decrease colchicine from an initial regimen of 0.6 mg twice daily to 0.3 mg once daily, or from an initial 0.6 mg once daily to 0.3 mg every other day. In familial Mediterranean fever, keep the maximum daily colchicine dose at 0.6 mg or less (this may be administered as 0.3 mg twice daily)2. When colchicine must be given together with a CYP3A4 inhibitor, adjust its dose by lowering either the daily amount or the frequency of dosing, and watch carefully for signs of colchicine toxicity3.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of colchicine
How to manage this interaction
This is a serious pairing, but your care team can manage it. Keep taking both medicines exactly as prescribed until you have spoken with your prescriber or pharmacist.
- Your team may lower your colchicine dose or take it less often while you are on idelalisib.
- If you have kidney or liver problems, this combination is generally avoided, so make sure your team knows your full history.
- They may monitor you more closely for signs of colchicine toxicity.
Call your care team right away if you notice severe diarrhea, vomiting, muscle weakness or pain, numbness, or unusual bruising, bleeding, or infections.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) While the interaction between colchicine and boceprevir has not been evaluated, an interaction between colchicine and clarithromycin, a potent CYP3A4 inhibitor, led to fatal colchicine toxicity. Colchicine Cmax and AUC rose by 227.2% and 281.5%, respectively, following a single 0.6 mg colchicine dose given to patients (n=23) who were receiving clarithromycin 250 mg twice daily for 7 days 21.
b) In a pharmacokinetic study, giving a single dose of colchicine to patients who had received ritonavir 100 mg twice daily for 5 days (n=18) produced a 184.4% and 296% increase in colchicine Cmax and AUC relative to baseline values, respectively 41.
Common questions
Can I take Idelalisib and Colchicine together?
Idelalisib blocks the enzyme that clears colchicine, which can push colchicine to dangerous, potentially fatal levels; this combination is contraindicated (especially with kidney or liver problems), so talk to your doctor or pharmacist before taking both. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Idelalisib and Colchicine 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 Idelalisib and Colchicine interaction managed?
This is a serious pairing, but your care team can manage it. Keep taking both medicines exactly as prescribed until you have spoken with your prescriber or pharmacist. Your team may lower your colchicine dose or take it less often while you are on idelalisib. If you have kidney or liver problems, this combination is generally avoided, so make sure your team knows your full history. They may monito… Management is individual — always follow your own care team's guidance.
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 Idelalisib or Colchicine 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 (4)
- 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
- Product Information: COLCRYS(TM) oral tablets, colchicine oral tablets. AR Scientific, Inc. Philadelphia, PA, 2009. DailyMed
Keep reading about Idelalisib
Keep reading about Colchicine
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