A man in his fifties pushed two boxes across the counter.
“These are both for gout, right? Taking both — isn’t that too much?”
Allopurinol in one box, colchicine in the other. His doctor had written both prescriptions that morning. He said the word “both” quietly, the way people do when they suspect the doctor but would rather not say so out loud.
Short answer: yes, they can be taken together. For most people who are just starting treatment, they should be.
Not the same job done twice. Allopurinol brings uric acid down. Colchicine, in this setting, prevents the attack that bringing uric acid down tends to trigger. One works for years. The other covers the first few months, then steps aside.
Why Lowering Uric Acid Makes Things Worse First
This is the part nobody explains to them, and it’s the reason the combination looks strange from the outside.
A gout attack starts with crystals. Urate crystals sit in a joint, the immune system recognizes them as foreign, and neutrophils pour in to deal with them. In people who have carried high uric acid for years, those crystals have usually been sitting there quietly for a long time without causing trouble.
Then allopurinol starts working. Blood uric acid falls, the deposits begin to dissolve, and small pieces break loose into the joint space. The immune system sees fresh crystals and reacts. So the first months of good treatment can be the most painful months the patient has had in years.
The drug is not failing. The uric acid is moving.
The 2020 American College of Rheumatology (ACR) guideline anticipates exactly this. When uric acid–lowering therapy is started, it recommends low-dose colchicine as prophylaxis for at least three months, and many clinicians continue it for six. The 2016 EULAR recommendations lean toward six months. The Colcrys label makes the same point in its own words: prophylaxis may be beneficial for at least the first six months.
One Drug Lowers Production. The Other Puts Out the Fire.
Allopurinol blocks xanthine oxidase, the enzyme that turns purines into uric acid. Less enzyme activity, less uric acid made. It does nothing for pain. Nothing for inflammation that is already running.
Colchicine does not act on uric acid at all. It disrupts the microtubules that neutrophils rely on to move, gather, and release inflammatory signals. The crystals stay where they are. The response to them doesn’t get going.
The two also leave the body by different roads. Allopurinol becomes oxypurinol and goes out through the kidney. Colchicine is handled by CYP3A4 and pumped back out of cells by P-glycoprotein. I’m not aware of a shared metabolic pathway between them, and nothing binds the two together in the gut. So the “they’ll fight each other” worry doesn’t have much to stand on. It just sounds sensible.
How It’s Actually Dosed
The starting dose of allopurinol is deliberately low. 100 mg once daily for most people, 50 mg when kidney function is reduced. From there, your doctor rechecks uric acid every two to four weeks and raises the dose step by step until it sits below 6 mg/dL, or 360 µmol/L. The titration is the prescriber’s job, not a number to chase at home. Two or three tablets on day one because the reading looks high is exactly how severe hypersensitivity reactions start.
Colchicine for prevention is a small dose. The label allows 0.6 mg once or twice a day, up to 1.2 mg a day, and most people starting out need only the once. In severe kidney impairment, the label starts at 0.3 mg a day; on dialysis, 0.3 mg twice a week. Those adjustments belong to the prescriber, not to arithmetic done at home.
No need to separate them by a couple of hours. Space them out and you’ve only added one more chance to forget a dose.
Where the Real Danger Sits
If you’d rather not find this out at the counter, the newsletter is free.
A woman came back on day three, still taking it, pleased with herself. The diarrhea, she told me, meant it was working. It doesn’t. I stopped her that afternoon.
Diarrhea is the first sign of colchicine toxicity. Three loose stools in a day, or anything watery, means hold the dose and call. Push through it and you can end up dehydrated; in bad cases the bone marrow takes the hit. Colchicine has a narrow therapeutic window. That’s why hospitals treat it as a high-alert medicine.
Allopurinol hypersensitivity is rarer, and worse. It starts as a rash and can progress to Stevens-Johnson syndrome. HLA-B*58:01 is the marker, and it is not spread evenly across populations. It is common in people of Han Chinese, Korean, and Thai descent — common enough that the ACR guideline recommends screening those patients before the first tablet. If that is your background, ask for the test; major reference labs in the US run it. If you are of European descent, the allele is uncommon and routine screening is not recommended. Where screening isn’t done, start at the lowest dose and watch the first three months for rash, fever, or mouth ulcers. Any of those, stop and get seen the same day.
Then there are other prescriptions. Clarithromycin, erythromycin, ketoconazole, itraconazole, ritonavir, verapamil, diltiazem, cyclosporine — all push colchicine levels up. Statins add muscle risk on top of that. None of these combinations is absolutely forbidden. Most of the time the colchicine dose gets cut back or paused for a while. Bring the full list to every visit instead of deciding alone. I wrote the longer gout drug interaction list separately, if you want it before the visit.
One more, because it’s the one that kills. Allopurinol with azathioprine or mercaptopurine. Block xanthine oxidase and those two drugs have no exit. Levels climb fast. The marrow goes.
Two Mistakes I See Often
First: stopping allopurinol once the pain clears. Uric acid stays low because the drug is still working. Stop, and it climbs back. The swinging is worse than the steady high. Current guidelines don’t even ask you to wait out a flare — treatment can start in the middle of one.
Second: the belief that two gout medicines at once must be hurting the kidneys. Kidneys do need watching. That part is true. Watching means creatinine checks and dose adjustments made by your doctor. It doesn’t mean dropping half the regimen and hoping.
Questions I Get Asked
Do they need to be taken at different times? No. Take them as prescribed.
How long does the colchicine part last? At least three months, often six. Longer if uric acid hasn’t reached target or flares keep coming.
Can allopurinol be started in the middle of an attack? Yes. The 2020 ACR guideline supports starting during a flare rather than waiting for it to settle.
When to Stop and Call Someone
- More than three loose stools a day.
- A new rash.
- Fever.
- Mouth ulcers.
- Noticeably less urine.
- Muscle pain or weakness.
- Easy bruising or bleeding.
Any one of those, stop the medicine and reach the prescriber the same day.
Two boxes, one purpose. Allopurinol is the long game. Colchicine is the guardrail for the months when the long game hurts.
Lin Kai, Licensed Pharmacist, 17 years hospital pharmacy — kailinpharmacist.com
Written in Chinese, brought into English with AI — the experience and the judgment are mine.
This article is general information, not medical advice. Dosing depends on kidney function, other medicines, and your own history. Talk with your prescriber or pharmacist before starting, stopping, or changing anything described here.
Related reading
- Gout medication interactions: what not to take together
- A gout flare while on warfarin: what pain relief is safe
- How many ibuprofen can you take in a day
Sources
- FitzGerald JD, et al. 2020 American College of Rheumatology Guideline for the Management of Gout. Arthritis Care Res (Hoboken). 2020;72(6):744-760. doi:10.1002/acr.24180 — https://doi.org/10.1002/acr.24180
- COLCRYS (colchicine) tablets, prescribing information. DailyMed. — DailyMed label
- Allopurinol tablets, prescribing information. DailyMed. — DailyMed label
- Cao ZH, et al. HLA-B*58:01 allele is associated with augmented risk for both mild and severe cutaneous adverse reactions induced by allopurinol in Han Chinese. Pharmacogenomics. 2012;13(10):1193-1201. — PubMed 22909208
- Richette P, et al. 2016 updated EULAR evidence-based recommendations for the management of gout. Ann Rheum Dis. 2017;76(1):29-42. doi:10.1136/annrheumdis-2016-209707 — https://doi.org/10.1136/annrheumdis-2016-209707
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