Pharmacokinetics and pharmacodynamics of different doses of Irtemazole in repeated application.

Irtemazole, a new uricosuric substance, was tested in 12 normouricemic subjects in doses between 6.25-37.5 mg applied twice daily for 7 days per os. The plasma uric acid level decreased in all subjects, to a constant level within 1-2 days with application of the higher doses, and within 2-3 days with application of the lower doses, and was maintained as long as irtemazole was given. The average decrease of plasma uric acid was 20.4% at a dose of 6.25 mg irtemazole, 22.7% at 12.5 mg, 42.0% at 25 mg, and 45.7% at 37.5 mg. The renal uric acid excretion and the uric acid clearance increased to a constant level within 1 day of irtemazole application. The initial levels of plasma uric acid, uric acid excretion, and uric acid clearance were reached after 1-2 days after cessation of irtemazole. Within 1 to 2 days after ingestion of irtemazole a constant plasma irtemazole level and renal irtemazole excretion were observed in all doses throughout the application period. One to 2 days after discontinuation of irtemazole it was no longer detectable in plasma and urine. No side effects were found.