In 2003, the uricosuric
drug benzbromarone was withdrawn from the market. The first alternative
drug of choice was the
xanthine oxidase inhibitor
allopurinol. The purpose was to (1) investigate the efficacy of
allopurinol (standard dosage) compared with previous treatment with
benzbromarone; and (2) investigate the combination
therapy allopurinol-
probenecid as an effective alternative treatment compared with previous
benzbromarone treatment. A prospective, open study was carried out in a cohort of 51
gout patients who discontinued
benzbromarone therapy because of market withdrawal. Patients were given 200-300 mg
allopurinol (stage 1). When
allopurinol failed to attain the target serum
urate (sUr) levels <or=0.30 mmol/l,
probenecid 1,000 mg/day was added (stage 2). Treatment with
benzbromarone monotherapy (range: 100-200 mg/day; mean 138 mg/day) resulted in 92% of patients reaching target levels sUr <or= 0.30 mmol/l with a decrease of 61[11]% compared to baseline. In stage 1, 32 patients completed treatment with
allopurinol monotherapy (range 200-300 mg/day; mean 256 mg/day), which resulted in 25% of patients attaining sUr target levels. Decrease in sUr levels was 36[11]%, which was significantly less compared to treatment with
benzbromarone (p < 0.001). In stage 2, 14 patients received
allopurinol-
probenecid combination
therapy, which resulted in 86% of patients attaining target sUr levels (after failure on
allopurinol monotherapy), which was comparable to previous treatment with
benzbromarone (p = 0.81). Decrease in sUr levels was 53[9]% (CI 95%: 48-58%), which was a non-significant difference compared to previous treatment with
benzbromarone (p = 0.23).
Benzbromarone is a very effective
antihyperuricemic drug with 91% success in attainment of target sUr levels <or=0.30 mmol/l.
Allopurinol 200-300 mg/day was shown to be a less potent alternative for most selected patients to attain target sUr levels (13% success). In patients failing on
allopurinol monotherapy, the addition of
probenecid proves to be an effective treatment strategy for attaining sUr target levels (86% success).