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Allopurinol dosage

Q: What is the usual dose of allopurinol?

The FDA label starts everyone at 100 mg orally daily, then raises it "with weekly increments of 100 mg, until a serum uric acid level of 6 mg/dL or less is reached." Where people land varies: the label says gout control is generally achieved with 200 mg to 300 mg daily in mild gout, and 400 mg to 600 mg daily in moderate to severe tophaceous gout. The minimal effective dosage is 100 mg to 200 mg daily. There is no standard dose — the dose is whatever gets urate to target for that person.

Q: What is the maximum dose of allopurinol?

800 mg daily. The label states verbatim: "the maximal recommended dosage is 800 mg daily." Anything above 300 mg should be split — "Doses in excess of 300 mg should be administered in divided doses." In kidney impairment there is no published ceiling; the label says the maximum "is not defined at different eGFR levels," which is why those patients are titrated in 50 mg steps every 2 to 4 weeks with kidney monitoring rather than pushed to the general maximum.

Q: Can you start allopurinol during a gout attack?

This one changed. The old teaching was to wait until a flare fully settled. The 2020 ACR gout guideline conditionally recommends starting urate-lowering therapy during a flare rather than waiting for it to resolve, on the evidence that therapy started during a flare does not increase or prolong symptoms as long as anti-inflammatory treatment is given. The FDA label does not prohibit starting during a flare either; it requires flare prophylaxis with colchicine or an anti-inflammatory agent upon initiation. Practically: allopurinol will not treat the attack you are having — it is a long-term urate-lowering drug — so the flare itself still needs its own treatment. Whether to start now or after is your prescriber's decision.

Q: Should you stop allopurinol during a flare?

No. The FDA label is unambiguous: "If a gout flare occurs during Allopurinol Treatment, Allopurinol Tablets need not be discontinued. Manage the gout flare concurrently, as appropriate for the individual patient." Flares in the first months are expected — falling urate mobilizes urate out of tissue deposits, which can trigger attacks even when levels look normal. The label instructs clinicians to "Advise patients to continue Allopurinol Tablets and prophylactic treatment even if gout flares occur, as it may take months to achieve control of gout flares." Stopping and restarting also re-exposes you to the early-therapy hypersensitivity risk window.

Q: What is the allopurinol dose with kidney disease?

Reduced, and titrated far more slowly, because allopurinol and its active metabolite oxypurinol are excreted by the kidney and accumulate in renal failure. The label's gout starting doses by eGFR: above 60 mL/minute, no dosage modification; above 30 to 60 mL/minute, 50 mg daily; above 15 to 30 mL/minute, 50 mg every other day; 5 to 15 mL/minute, 50 mg twice weekly; below 5 mL/minute, 50 mg once weekly. Increase "gradually in 50 mg/day increments every 2 weeks to 4 weeks" and use the lowest dose that reaches the target. Kidney function should be monitored closely at initiation, with the dose decreased or the drug withdrawn if abnormalities appear and persist. Note this does not mean people with CKD cannot take allopurinol — ACR 2020 keeps it first-line urate-lowering therapy including in CKD stage 3 or higher.

Q: How long does allopurinol take to work?

Uric acid levels start falling within days, but symptom control takes far longer. The label states that "Even with adequate therapy with Allopurinol Tablets, it may require several months to deplete the uric acid pool sufficiently to achieve control of the flares," and that flares "typically become shorter and less severe after several months of therapy." That is why flare prophylaxis is continued until urate has normalized and the patient has been free of gout flares for several months. Judge progress by repeat serum urate levels reaching 6 mg/dL or less, not by how you feel in week two.

Allopurinol is unusual among common prescriptions in that there is no single correct dose. The FDA label sets a starting point (100 mg daily), a ceiling (800 mg daily), and a target to titrate toward — a serum uric acid level of 6 mg/dL or less. Everything between those numbers is decided by lab results, not by body weight or a fixed schedule. Two things drive the dose more than anything else: how much urate is deposited in the body, and how well the kidneys work, since allopurinol and its active metabolite oxypurinol are cleared renally and accumulate in kidney impairment. The numbers below are quoted from the FDA-approved labeling for allopurinol tablets (2024 revision). We rate medications; we do not sell them, and this page is a reference, not a prescription.

This is reference, not a dosing instruction. Allopurinolis prescription-only and the dose is individualized and titrated by a prescriber to your condition, response, kidney/liver function and other medicines. The figures below are the FDA label’s — do not start, change or stop a dose based on this page.

By the pharmaranks editorial teamReviewed against the FDA label for Allopurinol sourcesUpdated Jul 20, 2026How we research

Approved for: Allopurinol is a xanthine oxidase inhibitor approved for three things: management of adults with signs and symptoms of primary or secondary gout (acute attacks, tophi, joint destruction, uric acid lithiasis, and/or nephropathy); management of hyperuricemia associated with cancer therapy in adults and pediatric patients; and management of recurrent calcium oxalate calculi in adults whose daily uric acid excretion exceeds 800 mg/day in male patients and 750 mg/day in female patients, despite lifestyle changes. It lowers uric acid production — it is not a painkiller and does nothing for the pain of a flare already underway.
Available as: Tablets: 100 mg and 300 mg, scored

Allopurinol dosage by use, from the FDA label
Use	What the label says
Gout — start and titrate	The label states: "The initial recommended dosage for the management of gout is 100 mg orally daily, with weekly increments of 100 mg, until a serum uric acid level of 6 mg/dL or less is reached." It adds that "Initiating treatment with lower dosages of Allopurinol Tablets and titrating slowly, decreases the risk of gout flares and drug induced serious adverse reactions." The minimal effective dosage is 100 mg to 200 mg daily. Before starting, the label directs baseline testing: serum uric acid, complete blood count, chemistry panel, liver function tests, and kidney function tests (serum creatinine and eGFR). Allopurinol is generally better tolerated if taken following meals, with fluid intake sufficient to yield a daily urinary output of at least 2 liters.
By severity (mild vs tophaceous)	The label: "In general, gout control is achieved with 200 mg to 300 mg daily in patients with mild gout, and with 400 mg to 600 mg daily in patients with moderate to severe tophaceous gout." These are typical landing points after titration, not starting doses — you still start at 100 mg daily and climb. The dose is a means to the urate target, so a person with mild gout may need 400 mg and a person with tophi may control at 300 mg. Gout attacks usually become shorter and less severe after several months of therapy.
Renal impairment	Allopurinol is renally cleared and accumulates in kidney impairment, so the label sets reduced starting doses by eGFR. For gout (Table 1): eGFR > 60 mL/minute — no dosage modification; > 30 to 60 mL/minute — 50 mg daily; > 15 to 30 mL/minute — 50 mg every other day; 5 to 15 mL/minute — 50 mg twice weekly; < 5 mL/minute — 50 mg once weekly. Titration is slower too: "increase the dose gradually in 50 mg/day increments every 2 weeks to 4 weeks in patients with renal impairment." The label explicitly notes that "The maximum dosage that should be used in patients with various levels of renal impairment is not defined at different eGFR levels" — so the ceiling in kidney disease is a clinical judgment, not a published number. For hyperuricemia associated with cancer therapy (Table 2): eGFR 10-20 mL/min — 200 mg/day; < 10 mL/min — 100 mg/day; on dialysis — 50 mg every 12 hours, or 100 mg every 24 hours.
Hyperuricemia with cancer therapy (tumor lysis)	Adults: 300 mg to 800 mg orally daily, started 24 hours to 48 hours before chemotherapy known to cause tumor cell lysis. Pediatric patients: 100 mg/m2 orally every 8 hours to 12 hours (10 mg/kg/day, maximum 800 mg/day). Serum uric acid is monitored at least daily, and allopurinol is discontinued when the risk of tumor lysis has abated (2 days to 3 days from start of chemotherapy).
Recurrent calcium oxalate stones	"The recommended dosage for the management of recurrent calcium oxalate stones in hyperuricosuric patients is 200 mg to 300 mg orally daily in divided doses or as the single equivalent," adjusted based on subsequent 24-hour urinary urate determinations. The label notes data are insufficient to give dosage recommendations for this use in patients with renal impairment.

Maximum dose

"The minimal effective dosage is 100 mg to 200 mg daily and the maximal recommended dosage is 800 mg daily." That 800 mg/day ceiling applies to gout and to hyperuricemia with cancer therapy alike (pediatric tumor-lysis dosing is capped at the same 800 mg/day). In renal impairment, the label states the maximum "is not defined at different eGFR levels" — there is no published upper limit for reduced kidney function, which is a reason those patients are titrated slowly and monitored rather than pushed toward 800 mg.

Dose adjustments

Two adjustments matter. First, splitting: "The appropriate dosage may be administered in divided doses or as a single equivalent dose with the 300 mg tablet. Doses in excess of 300 mg should be administered in divided doses." So 300 mg can be one daily tablet; 400 mg and above should be split. Second, kidney function. Gout starting doses by eGFR (label Table 1): > 60 mL/min, no modification; > 30 to 60 mL/min, 50 mg daily; > 15 to 30 mL/min, 50 mg every other day; 5 to 15 mL/min, 50 mg twice weekly; < 5 mL/min, 50 mg once weekly. Titrate in 50 mg/day increments every 2 to 4 weeks and use the lowest dose that achieves the urate target. The label directs monitoring kidney function during the early stages of administration and decreasing the dosage or withdrawing the drug if persistent abnormalities in kidney function occur. If a dose is missed, "there is no need to double the dose at the next scheduled time."

Dosing safety — read before you rely on any number

Do not stop allopurinol because a flare happens. This is the single most common self-inflicted error. The label is explicit: "If a gout flare occurs during Allopurinol Treatment, Allopurinol Tablets need not be discontinued. Manage the gout flare concurrently." Flares during the first months are expected — they happen "even when normal or subnormal serum uric acid levels have been attained due to the mobilization of urates from tissue deposits." Patients are told to "continue Allopurinol Tablets and prophylactic treatment even if gout flares occur, as it may take months to achieve control of gout flares." Take flare prophylaxis when starting: "Flare prophylaxis with colchicine or an anti-inflammatory agent according to practice guidelines is recommended upon initiation of Allopurinol Tablets," continued until serum uric acid has normalized and the patient has been free of gout flares for several months (ACR 2020 suggests three to six months). On starting during an active flare, the older belief that you must wait for a flare to fully resolve is not what current guidance says: the 2020 ACR guideline conditionally recommends starting urate-lowering therapy during a flare rather than waiting, provided anti-inflammatory treatment is given — this is a prescriber's call, not a self-directed one. Rash is a stop-and-call-now event. Serious and sometimes fatal dermatologic reactions, including toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), and drug reaction with eosinophilia and systemic symptoms (DRESS), occur in approximately 5 in 10,000 (0.05%) patients taking allopurinol. The label: "Discontinue Allopurinol Tablets permanently at the first appearance of skin rash or other signs which may indicate a hypersensitivity reaction" and "Instruct patients to discontinue Allopurinol Tablets and to seek medical attention immediately, at the first sign of a skin rash." The HLA-B*58:01 allele raises that risk; its frequency "ranges from 8 to 10% in Han Chinese populations, about 8% in Thai populations, and about 6% in Korean populations," about 4% in Blacks, about 1% to 2% in indigenous peoples of the Americas and Hispanic populations, and < 1% in people of European descent and Japanese. The label advises considering screening before starting in patients from high-prevalence populations and says allopurinol is not recommended in HLA-B*58:01 positive patients unless benefits clearly outweigh risks — but SJS/TEN "can still occur in patients who are found to be negative for HLA-B*5801 irrespective of ethnic origin." Risk is largely confined to the first few months of therapy. Hypersensitivity risk may also be increased with concurrent thiazide diuretics in decreased kidney function, and rash risk increases with bendamustine, ampicillin, and amoxicillin.

Bottom line

Allopurinol is dosed to a lab number, not to a symptom. Start 100 mg daily (50 mg or less in kidney impairment), climb by 100 mg weekly, and stop climbing when serum uric acid is 6 mg/dL or less — anywhere from 100 mg to the labeled maximum of 800 mg daily, split into divided doses above 300 mg. Kidney function sets the starting dose and the pace of titration. Take flare prophylaxis for the first months, keep taking allopurinol through any flare that happens, and stop immediately and get medical attention for any rash. Every dose change belongs to the prescriber, guided by repeat urate levels.

Frequently asked questions

What is the usual dose of allopurinol?

The FDA label starts everyone at 100 mg orally daily, then raises it "with weekly increments of 100 mg, until a serum uric acid level of 6 mg/dL or less is reached." Where people land varies: the label says gout control is generally achieved with 200 mg to 300 mg daily in mild gout, and 400 mg to 600 mg daily in moderate to severe tophaceous gout. The minimal effective dosage is 100 mg to 200 mg daily. There is no standard dose — the dose is whatever gets urate to target for that person.

What is the maximum dose of allopurinol?

800 mg daily. The label states verbatim: "the maximal recommended dosage is 800 mg daily." Anything above 300 mg should be split — "Doses in excess of 300 mg should be administered in divided doses." In kidney impairment there is no published ceiling; the label says the maximum "is not defined at different eGFR levels," which is why those patients are titrated in 50 mg steps every 2 to 4 weeks with kidney monitoring rather than pushed to the general maximum.

Can you start allopurinol during a gout attack?

This one changed. The old teaching was to wait until a flare fully settled. The 2020 ACR gout guideline conditionally recommends starting urate-lowering therapy during a flare rather than waiting for it to resolve, on the evidence that therapy started during a flare does not increase or prolong symptoms as long as anti-inflammatory treatment is given. The FDA label does not prohibit starting during a flare either; it requires flare prophylaxis with colchicine or an anti-inflammatory agent upon initiation. Practically: allopurinol will not treat the attack you are having — it is a long-term urate-lowering drug — so the flare itself still needs its own treatment. Whether to start now or after is your prescriber's decision.

Should you stop allopurinol during a flare?

No. The FDA label is unambiguous: "If a gout flare occurs during Allopurinol Treatment, Allopurinol Tablets need not be discontinued. Manage the gout flare concurrently, as appropriate for the individual patient." Flares in the first months are expected — falling urate mobilizes urate out of tissue deposits, which can trigger attacks even when levels look normal. The label instructs clinicians to "Advise patients to continue Allopurinol Tablets and prophylactic treatment even if gout flares occur, as it may take months to achieve control of gout flares." Stopping and restarting also re-exposes you to the early-therapy hypersensitivity risk window.

What is the allopurinol dose with kidney disease?

Reduced, and titrated far more slowly, because allopurinol and its active metabolite oxypurinol are excreted by the kidney and accumulate in renal failure. The label's gout starting doses by eGFR: above 60 mL/minute, no dosage modification; above 30 to 60 mL/minute, 50 mg daily; above 15 to 30 mL/minute, 50 mg every other day; 5 to 15 mL/minute, 50 mg twice weekly; below 5 mL/minute, 50 mg once weekly. Increase "gradually in 50 mg/day increments every 2 weeks to 4 weeks" and use the lowest dose that reaches the target. Kidney function should be monitored closely at initiation, with the dose decreased or the drug withdrawn if abnormalities appear and persist. Note this does not mean people with CKD cannot take allopurinol — ACR 2020 keeps it first-line urate-lowering therapy including in CKD stage 3 or higher.

How long does allopurinol take to work?

Uric acid levels start falling within days, but symptom control takes far longer. The label states that "Even with adequate therapy with Allopurinol Tablets, it may require several months to deplete the uric acid pool sufficiently to achieve control of the flares," and that flares "typically become shorter and less severe after several months of therapy." That is why flare prophylaxis is continued until urate has normalized and the patient has been free of gout flares for several months. Judge progress by repeat serum urate levels reaching 6 mg/dL or less, not by how you feel in week two.

Sources

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Doses are transcribed from the FDA-approved label and are general reference information, not medical advice or a personal dose. Only a prescriber can set or change your dose. If you think you took too much, contact Poison Control (1-800-222-1222) or 911.