Rapid onset of uricosuria after oral administration of irtemazole, an uricosuric substance.

A single 50 mg dose of irtemazole was given orally to ten healthy male volunteers. The onset of effects was tested. Plasma uric acid began to decrease 15 to 25 min after irtemazole was administrated. Renal uric acid excretion and uric acid clearance increased 10 to 20 min after drug administration. Maximal renal uric acid excretion (mean 197.4 mg/h) and maximal uric acid clearance (mean 78.4 ml/min) were reached after 15 to 55 min. No side effects were observed. The effects of irtemazole occur earlier than those of benzbromarone. The therapeutic effects of long-term therapy remain to be investigated.