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Acute Effects of Oral Tofisopam on Plasma Concentration and Urinary Excretion of Uric Acid and Oxypurinol ‚ÄúPreliminary Communication‚ÄĚ

[ Vol. 10 , Issue. 2 ]

Author(s):

Miki Hatayama, Chihiro Sumida, Masafumi Kurajoh, Jun Shiraishi, Hirokazu Okazaki, Takuhito Shoji, Hidenori Koyama, Zenta Tsutsumi, Yuji Moriwaki, Mitsuyoshi Namba and Tetsuya Yamamoto Pages 160-164 (5)

Abstract:


The effects of tofisopam, a GABA-receptor agonist, following oral administration (300mg) with and without allopurinol pretreatment on the plasma concentration and renal transport of uric acid and oxypurinol were investigated in 5 healthy subjects. Fractional and urinary excretions of uric acid were both significantly increased at 2-3 hours after tofisopam administration (559% and 459%, respectively), while plasma uric acid concentration was significantly decreased (36%) at 2.5 hours, suggesting that tofisopam affects uric acid metabolism via the tubular transport system. The hypouricemic effect of tofisopam was comparable to or greater than that of losartan and/or fenofibrate, which also have uric acid-lowering activity. In addition, with prior administration of allopurinol, the fractional and urinary excretions of oxypurinol were increased at 2-3 hours after tofisopam administration (51% and 33%, respectively), while the plasma oxypurinol concentration was significantly decreased at 1.5 and 2.5 hours (15% and 21%, respectively). Accordingly, tofisopam may be an attractive compound for treatment of hyperuricemia and/or gout, especially in patients complicated with autonomic dysfunction symptoms, though it is possible that the uric acid-lowering effect of oxypurinol is attenuated by tofisopam.

Keywords:

Allopurinol, hyperuricemia, levotofisopam, renal transport, uricosurics

Affiliation:

Division of Endocrinology and Metabolism, Department of Internal Medicine, Hyogo College of Medicine Mukogawa-cho 1-1, Nishinomiya, Hyogo 663-8501, Japan.



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