Colchicine and Saquinavir: 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
Saquinavir
No brand names on recordColchicine
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.
Saquinavir can make colchicine build up in your body to dangerous levels. Saquinavir is a protease inhibitor that blocks a liver enzyme (called CYP3A4) that normally breaks down colchicine. When that clean-up slows down, colchicine can climb too high. This matters a lot because colchicine has a narrow safety window, and too much has caused severe, even life-threatening poisoning, with symptoms like bad diarrhea, vomiting, muscle weakness, and blood problems.
Please don't stop or change either medicine on your own. This is a serious combination, so talk with your pharmacist or doctor promptly. They can decide on the safest plan, which often means avoiding the combination or carefully adjusting your colchicine dose and watching you closely.
Mechanism: Saquinavir is a strong CYP3A4 inhibitor (and P-gp inhibitor); colchicine is a CYP3A4/P-gp substrate. Inhibition reduces colchicine metabolism and efflux, increasing colchicine exposure. Neither drug is a prodrug here, so effect is increased colchicine toxicity.
Direction/magnitude: Increased colchicine AUC/Cmax; life-threatening and fatal toxicity reported at therapeutic doses. Evidence: probable.
- Contraindicated in renal or hepatic impairment.
- Normal renal/hepatic function: dose reduction required (recent use within 14 days counts).
- Gout flare: 0.6 mg once, then 0.3 mg 1 h later; repeat no sooner than 3 days.
- Prophylaxis and FMF: reduce dose/frequency per labeling.
- Monitor closely for colchicine toxicity (GI, myelosuppression, neuromyopathy).
What happens
Increased colchicine exposure and an increased risk of fatal toxicity
Interaction Deep Dive
Because life-threatening and fatal colchicine toxicity has occurred in patients taking colchicine at therapeutic doses together with strong CYP3A4 inhibitors, combining these agents is contraindicated1. In individuals with renal or hepatic impairment, the concurrent use of colchicine and strong CYP3A4 inhibitors (which encompass all protease inhibitors other than fosamprenavir) is likewise contraindicated. When patients have normal renal and hepatic function and are receiving, or have received within the previous 14 days, a strong CYP3A4 inhibitor, the colchicine dose must be modified. To treat a gout flare, lower the colchicine dose to a single 0.6 mg tablet, followed 1 hour later by 0.3 mg, and do not repeat the dose sooner than 3 days. For gout flare prophylaxis, decrease colchicine either from 0.6 mg twice daily down to 0.3 mg once daily, or from 0.6 mg once daily down to 0.3 mg once every other day. In the treatment of familial Mediterranean fever, the total daily colchicine dose should not exceed 0.6 mg (which may be administered as 0.3 mg twice daily)2. When colchicine must be given alongside CYP3A4 inhibitors that additionally inhibit P-gp4, adjust colchicine by lowering either the daily dose or the frequency of dosing. 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 high-risk combination, so let your care team lead. Keep taking both exactly as currently prescribed until you speak with them, and reach out promptly.
- If you have kidney or liver problems, this pairing is generally avoided.
- If your kidney and liver function are normal, your colchicine dose may be reduced or spaced out and individualized by your team, even if you took saquinavir within the past 2 weeks.
- Your team may monitor you more closely for colchicine toxicity.
Watch for and report right away: severe diarrhea, vomiting, muscle weakness or pain, numbness, unusual bruising, or signs of infection.
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 investigated, an interaction between colchicine and clarithromycin, a potent CYP3A4 inhibitor, produced fatal colchicine toxicity. Colchicine Cmax and AUC rose by 227.2% and 281.5%, respectively, when a single 0.6 mg dose of colchicine was 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) led to a 184.4% and 296% increase in colchicine Cmax and AUC compared with baseline levels, respectively 51.
Common questions
Can I take Colchicine and Saquinavir together?
Saquinavir blocks the enzyme that clears colchicine, so colchicine can rise to toxic, potentially fatal levels; this combination is contraindicated in kidney or liver impairment and requires a reduced, closely monitored colchicine dose otherwise. Contact your pharmacist or doctor before taking these together. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colchicine and Saquinavir 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 Saquinavir interaction managed?
This is a high-risk combination, so let your care team lead. Keep taking both exactly as currently prescribed until you speak with them, and reach out promptly. If you have kidney or liver problems, this pairing is generally avoided. If your kidney and liver function are normal, your colchicine dose may be reduced or spaced out and individualized by your team, even if you took saquinavir within th… 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 Colchicine or Saquinavir 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 (5)
- 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: MITIGARE(R) oral capsules, colchicine oral capsules. Hikma Specialty USA Inc (per FDA), Columbus, OH, 2024. DailyMed
- Product Information: COLCRYS(TM) oral tablets, colchicine oral tablets. AR Scientific, Inc. Philadelphia, PA, 2009. DailyMed
Keep reading about Saquinavir
Keep reading about Colchicine
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