Part 3 · Lowering urate
Treat to target
Urate-lowering therapy starts low and rises in small steps until a blood test shows serum urate below 6 mg/dL [360 µmol/L]. Scrub through two years of one imagined person: the dose staircase, the urate checks, the extra flares of the first months and the prophylaxis that covers them.
Doses here are quoted as published, not as instructions. The simulator follows the ACR 2020 guideline, the US labels and the trials named under each step; a dose for any person is set by their own clinician. 127,129,135
Schematic: one simulated person, not a prediction. The person starts at 9.0 mg/dL. Each 100 mg of allopurinol lowers urate by about 1 mg/dL up to 300 mg, a derived figure (arithmetic on Perez-Ruiz 1998's 2.75–3.34 mg/dL fall on 300 mg, not stated by any source), and by less above that. Steps every 4 weeks sit inside ACR's 2–5 weeks. The flare-rate curve is shaped to pass through Borstad 2004's average flare counts with and without colchicine; those averages are drawn as marked segments. Missed tablets are drawn at random. 26,135,311
What a nurse-led programme changed
Real trial data from Doherty 2018 (517 people in UK primary care), at baseline, 1 year and 2 years. The lines only join the three time points; nothing between them was measured. 95
Published titration schedules
| Source | Start | Steps | Ceiling |
|---|---|---|---|
| ACR 2020 (allopurinol) | ≤100 mg/day; lower in CKD stage ≥3, and "even lower initial allopurinol doses (e.g., ≤50 mg/day) should be considered in patients with CKD" | "Weeks to months, not years"; cites the 2012 advice of every 2–5 weeks, with serum urate after each step | Dose to target, not to a fixed cap 135 |
| US allopurinol label | 100 mg/day | +100 mg each week until serum urate ≤6 mg/dL | 800 mg/day 129 |
| UK allopurinol SmPC | 100 mg/day | 300–600 mg/day moderately severe, 700–900 mg/day severe | 900 mg/day 370 |
| EULAR 2016 | 100 mg/day | +100 mg every 2–4 weeks detail not confirmed in the full text | Adjusted to kidney function 331 |
| Doherty 2018 (nurse-led) | 100 mg/day | +100 mg every 3–4 weeks; then febuxostat 80→120 mg or benzbromarone 50→200 mg | 900 mg/day 95 |
| US febuxostat label | 40 mg/day | 80 mg if serum urate is still ≥6 mg/dL after 2 weeks | 80 mg; 40 mg in severe renal impairment 127 |
| EU febuxostat SmPC | 80 mg/day | 120 mg considered if serum urate is >6 mg/dL (357 µmol/L) after 2–4 weeks | 120 mg 107 |
| STOP Gout trial | Allopurinol 100 mg; febuxostat 40 mg | Titrated over 24 weeks | 800 mg; 120 mg 298 |
Most people need more than 300 mg
21–53%reached serum urate <6 mg/dL on allopurinol 300 mg/day across FACT, APEX, CONFIRMS and a Spanish study. 18,19,311,357
Escalating above the creatinine-clearance dose brought 69% to target at 12 months against 32% on a fixed dose, in a trial where 52% had CrCl <60. 382 When the control group then escalated too, urate fell a further 1.1 mg/dL. 381
Febuxostat by dose
Serum urate <6 mg/dL in 45% on 40 mg and 67% on 80 mg in CONFIRMS; 53% on 80 mg and 62% on 120 mg in FACT. 18,19
In STOP Gout (940 veterans, at least a third with CKD stage 3), 80% reached target on either drug, and allopurinol was non-inferior for flares (36.5% vs 43.5% in the final phase). 298
Starting during a flare
ACR 2020 conditionally recommends starting during a flare once treatment is indicated, rather than waiting. 135 In a 57-man trial, allopurinol 300 mg started during a flare (with indomethacin and colchicine for all) did not worsen pain, and urate fell from 7.8 to 5.9 mg/dL by day 3. 401 In a second trial the flare was not prolonged (15.4 vs 13.4 days, P = 0.5). 162
The older probenecid label says to wait "until an acute gouty attack has subsided". 126
Missed tablets Established
46%took at least 80% of their urate-lowering therapy, pooled across 13 studies; non-persistence ran from 54% to 87%. 352
A pharmacist-led, mostly automated telephone programme lifted adherence from 37% to 50% and target attainment from 15% to 30% at 1 year. 262 Only 12% of people on urate-lowering therapy knew about flares at the start. 158
Not too low? Unverified detail
EULAR 2016 sets <6 mg/dL [360 µmol/L], or <5 mg/dL [300 µmol/L] in severe gout. 331 Secondary sources also report EULAR advising against serum urate <3 mg/dL [180 µmol/L] over the long term; this guide could not confirm that line in the full text. 331 ACR 2020 sets <6 mg/dL for everyone on therapy (strong, high certainty). 135
How long to continue
ACR 2020 conditionally recommends continuing indefinitely (very low certainty). In the withdrawal series it cites, only 13% (27/211) stayed flare-free over 5 years off therapy. 135
Early evidence Perez-Ruiz 2006 suggested 5-year intermittent therapy for people with good control. 314 Hypothesis GO TEST Finale is randomising people in remission to continue or to taper and stop; only its protocol is published. 309
Covering the first months
| Source | Prophylaxis advice |
|---|---|
| ACR 2020 | Strong: colchicine, an NSAID or prednisone/prednisolone for 3–6 months rather than <3 months, continuing if flares persist 135 |
| EULAR 2016 | First 6 months, colchicine 0.5–1 mg/day or a low-dose NSAID detail not confirmed in the full text 331 |
| US colchicine label | Prophylaxis 0.6 mg once or twice daily, maximum 1.2 mg/day 117 |
| Febuxostat labels | EU: at least 6 months; US: "may be beneficial for up to six months" 107,127 |
| Pegloticase label | At least the first 6 months 122 |
| Pooled febuxostat trials | Flares rose to as much as 40% when 8 weeks of prophylaxis stopped, but stayed at 3–5% at the end of 6 months of it 433 |
| FORTUNE-1 | Flares in 12 weeks: 36.0% on fixed febuxostat 40 mg, 20.8% when stepped up from 10 mg, 18.9% on fixed 40 mg plus colchicine 0.5 mg/day (not significant after correction for multiple comparisons) 439 |