Table 2 Efficacy of allopurinol 300–600 mg/day versus benzbromarone 100–200 mg/day after stage 1 and stage 2*
AllopurinolBenzbromaronep Value
Stage 1 and 2 results(n = 27)(n = 23)
Dose (mg/day)300–600100–200
Treatment goal reached
    sUr ⩽0.30 mmol/l21 (78%)18 (78%)1.00
    95% CI59–89%58–90%
Treatment goal not reached
    Withdrawn because of ADRs2 (7%)3 (13%)0.62
    sUr 0.31–0.36 mmol/l2 (7%)2 (9%)1.00
    sUr >0.36 mmol/l2 (7%)0 (0%)0.34
Stage 1 results(n = 31)(n = 25)
Dose (mg/day)300100
Duration (months)2.3 (0.8)2.2 (0.7)0.93
    Range1.5–4.91.6–3.2
Treatment goal reached
    sUr ⩽0.30 mmol/l8 (26%)13 (52%)0.049
    95% CI12–45%33–70%
Treatment goal not reached
    Withdrawn because of ADRs2 (7%)3 (12%)0.62
    sUr 0.31–0.36 mmol/l12 (39%)2 (8%)0.01
    sUr >0.36 mmol/l8 (27%)7 (28%)1.00
sUr reached (mmol/l)0.34 (0.08)0.29 (0.08)–
    Range0.21–0.490.16–0.45
ΔsUr from baseline (%)−33 (13)−42 (15)0.04
uUr (mmol/day)2.2 (1.2)4.4 (1.7)<0.001
    Range0.5–6.11.5–8.4
UrCl (ml/min per 1.73 m2)3.6 (1.5)4.9 (2.2)<0.001
    Range1.0–8.03.0–20.6
Serum oxipurinol (mg/l)13.1 (10.4)––
    Range3.9–51.3
Stage 2 results*(n = 17)(n = 7)
Dose (mg/day)600200
Duration (months)2.5 (0.7)2.3 (0.8)0.71
    Range1.5–4.91.6–3.2
sUr reached (mmol/l)0.27 (0.07)0.28 (0.04)–
    Range0.18–0.380.23–0.35
ΔsUr from baseline (%)−49 (14)−46 (8)–
ΔsUr from stage 1 (%)−32 (16)−29 (6)–
uUr (mmol/day)2.1 (1.0)4.9 (2.2)–
    Range1.1–3.52.1–8.1
UrCl (ml/min per 1.73 m2)4.3 (1.5)10.3 (3.7)–
    Range2.0–6.64.6–15.3
Serum oxipurinol (mg/l)17.0 (9.9)––
    Range4.9–41.7

  • Data are number (%) or mean (SD) and range, unless stated otherwise.

  • *No statistical comparisons were performed for stage 2 results because of incomparable groups due to selection bias.

  • ADR, adverse drug reaction; sUr, serum urate concentration; UrCl, urate clearance; uUr, urate excreted in urine.