Drug Interaction Report

Istradefylline and Colchicine: Interaction Details

A pharmacist-reviewed analysis of the Istradefylline and Colchicine interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Istradefylline

Nourianz Nourianz®
+

Colchicine

Colcrys Colcrys® Gloperba Gloperba® Lodoco Mitigare
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Contraindicated
These should generally not be used together.
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.

Of 87 documented Istradefylline interactions, 2 are rated contraindicated — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
probable
Severity
Contraindicated

What happens

Increased colchicine exposure and an increased risk of fatal toxicity

Interaction Deep Dive

Concomitant use of colchicine with P-gp inhibitors is contraindicated1. Concomitant use of colchicine with CYP3A4 inhibitors that are also P-gp inhibitors has the potential for serious and life-threatening toxicity. If coadministration of colchicine and a P-gp inhibitor is necessary, the dose of colchicine should be adjusted by either reducing the daily dose by 50% to 75% 2 or reducing the dose frequency. Additionally, concomitant use of colchicine with P-gp and CYP3A4 inhibitors is contraindicated in patients with renal or hepatic impairment 2. Combining these inhibitors with colchicine in patients with renal and hepatic impairment has resulted in life-threatening or fatal colchicine toxicity 3.

Why it happens (mechanism)

Inhibition of P-gp-mediated efflux transport of colchicine; inhibition of CYP3A4-mediated metabolism of colchicine

Common questions

Can I take Istradefylline and Colchicine together?

Increased colchicine exposure and an increased risk of fatal toxicity Always confirm with your pharmacist or prescriber before making any change.

How serious is the Istradefylline 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 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 Istradefylline 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 (3)

  1. Product Information: LODOCO(R) oral tablets, colchicine oral tablets. AGEPHA Pharma USA, LLC (per FDA), Parsippany, NJ, 2023. DailyMed
  2. Hansten PD, Tan MS, Horn JR, et al: Colchicine drug interaction errors and misunderstandings: recommendations for improved evidence-based management. Drug Saf 2023; 46(3):223-242. PubMed
  3. Product Information: MITIGARE(R) oral capsules, colchicine oral capsules. Hikma Specialty USA Inc (per FDA), Columbus, OH, 2024. DailyMed
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Istradefylline

Keep reading about Istradefylline

All Istradefylline interactions (87) Istradefylline drug information
Also serious with: Ensitrelvir Morphine Injection Ketoconazole Indinavir
Colchicine

Keep reading about Colchicine

All Colchicine interactions (223) Colchicine drug information
Also serious with: Zanubrutinib Ketoconazole Topical Alogliptin Amiodarone
Beyond drug–drug

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:

Istradefylline + Activated Charcoal Grapefruit St. John's Wort Acacia Rigidula Adrafinil African Wild Potato American Elder Astaxanthin + 130 more
Colchicine + Activated Charcoal Autumn Crocus Grapefruit St. John's Wort Acacia Rigidula Adrafinil African Wild Potato American Elder + 138 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.