Colchicine and Conivaptan: 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
Conivaptan
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.
These two medicines can be a dangerous combination. Conivaptan (Vaprisol) strongly blocks two of the main pathways your body uses to break down and clear colchicine. When those pathways are blocked, colchicine can build up to high levels, even at normal doses.
Too much colchicine can cause serious, sometimes life-threatening problems like severe diarrhea, muscle weakness, and damage to blood cells. This is considered a combination to avoid, especially if you have kidney or liver problems. Please don't stop either medicine on your own. Talk with your pharmacist or doctor. They can safely manage this by adjusting your colchicine dose, spacing out the timing, or choosing a different option.
Direction: Conivaptan (dual strong CYP3A4 and P-gp inhibitor) reduces colchicine metabolism and efflux, increasing colchicine exposure and toxicity risk. Colchicine is a CYP3A4/P-gp substrate (not a prodrug).
- Severity: Contraindicated; fatal colchicine toxicity reported at therapeutic doses.
- Contraindicated absolutely in renal or hepatic impairment.
- Evidence: Theoretical/mechanistic, but supported by documented outcomes with this inhibitor class.
- Management (normal renal/hepatic function only): reduce colchicine dose or frequency and monitor for toxicity (GI symptoms, myelosuppression, neuromyopathy).
- Applies to concurrent or recent (last 14 days) conivaptan; restart colchicine no sooner than 1 week after stopping conivaptan.
What happens
Increased colchicine exposure and an increased risk of colchicine toxicity
Interaction Deep Dive
Both CYP3A4 and P-gp metabolize colchicine, which is a substrate of each. Because life-threatening and fatal colchicine toxicity has occurred in patients taking colchicine at therapeutic doses together with dual strong inhibitors of CYP3A4 and P-gp, this combination is contraindicated1. Likewise, pairing colchicine with a dual CYP3A4 and P-gp inhibitor such as conivaptan is contraindicated in individuals who have renal or hepatic impairment. When such combined therapy is necessary in patients whose hepatic and renal function is normal, the colchicine dose should be modified by lowering either the daily amount or the frequency of dosing, and the patient should be closely watched for signs of colchicine toxicity3. In patients with normal renal and hepatic function, a colchicine dose adjustment is needed when conivaptan has been used concurrently or recently (within the last 14 days). When treating a gout flare, cut the colchicine dose to a single 0.6 mg tablet followed 1 hour later by 0.3 mg (half a tablet), and do not repeat the dose sooner than 3 days. For gout flare prophylaxis, reduce colchicine from an original 0.6 mg twice daily to 0.3 mg once daily, or from an original 0.6 mg once daily to 0.3 mg once every other day. When treating familial Mediterranean fever, the colchicine dose should not exceed a maximum of 0.6 mg per day (which may be administered as 0.3 mg twice daily)2. Colchicine should not be started until at least 1 week has passed after conivaptan therapy is finished4.
Why it happens (mechanism)
Inhibition of CYP3A-mediated metabolism of colchicine; inhibition of P-gp-mediated efflux transport of colchicine
How to manage this interaction
This combination is generally avoided. Your care team decides the safest path, which may mean using an alternative or carefully adjusting colchicine.
- If you have kidney or liver problems, this combination is not used.
- With normal kidney and liver function, if both are truly needed, your team will reduce your colchicine dose or how often you take it and watch you closely for toxicity.
- These precautions also apply if you took conivaptan within the last 14 days, and colchicine is typically restarted no sooner than 1 week after conivaptan ends.
Keep taking your medicines as prescribed and ask your pharmacist or prescriber before making any change.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
4 reports — tap to read
a) When given intravenously at 40 mg/day, the potent CYP3A inhibitor conivaptan raised the AUC of the CYP3A substrate midazolam by roughly 100% following a 1-mg IV dose and by 200% following a 2-mg oral dose 4.
b) Intravenous conivaptan at 30 mg/day produced a threefold rise in the AUC of simvastatin, a CYP3A substrate 4.
c) Oral conivaptan at 40 mg twice daily led to a doubling of both the AUC and the half-life of amlodipine, a CYP3A substrate 4.
d) In a study involving 23 patients, taking a 0.6 mg dose of colchicine together with clarithromycin 250 mg twice daily for 7 days produced increases from baseline of 227.2% in colchicine Cmax and 281.5% in colchicine AUC 2.
Common questions
Can I take Colchicine and Conivaptan together?
Conivaptan can push colchicine levels dangerously high, so this pairing is contraindicated (especially with kidney or liver problems); do not combine them without your care team adjusting the colchicine dose or choosing another option. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colchicine and Conivaptan 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 Conivaptan interaction managed?
This combination is generally avoided. Your care team decides the safest path, which may mean using an alternative or carefully adjusting colchicine. If you have kidney or liver problems, this combination is not used. With normal kidney and liver function, if both are truly needed, your team will reduce your colchicine dose or how often you take it and watch you closely for toxicity. These precaut… 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 Conivaptan 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: VAPRISOL(R) intravenous injection, conivaptan HCl intravenous injection. Cumberland Pharmaceuticals Inc (per FDA), Nashville, TN, 2016.
Keep reading about Conivaptan
Keep reading about Colchicine
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