Mechanism of the Uricosuric Activity of Ticrynafen

Studies employing pyrazinamide, which have included the measurements of clearances of pyrazinamide and pyrazinoate, as well as of ticrynafen itself and its principal metabolite, have lent support to the hypothesis that ticrynafen inhibits the tubular reabsorption of both filtered and secreted urate by nephrons of the human kidney. The inhibition of the reabsorption of secreted urate by ticrynafen appears to be quantitatively important for eliciting its uricosuric and hypouricemic responses. Because the uricosuric and natriuretic responses correlate with urinary ticrynafen concentrations, the drug appears to inhibit tubular reabsorption after gaining access to tubule fluid. As a consequence of its extensive binding to plasma proteins, clearance data suggest that tubular secretion of ticrynafen is necessary for its action.