[On the dose-effect relation of allopurinol (author's transl)]

The hypuricemic action(y) of 1H-pyrazolo(3,4-d)pyrimidin-4-ol (allopurinol) is dependent on the serum concentration of uric acid (x). After treatment with allopurinol at doses of 300 mg daily for 8 days there exists a highly significant correlation corresponding the equation y = 0.875x + 3.950. At a level of 8 mg/dl without any therapy serum uric acid concentration is expected to decrease by an average of 3 mg/dl if allopurinol is applied at daily doses of 300 mg in a preparation with or without any retarding effect. Following a dose reduction to 150 mg allopurinol daily over a period of 8 days, too, the mean diminution of the hypuricemic action amounts only to 0.43 +/- 0.26 mg/dl (S.D.). In some cases, however, long-term therapy with allopurinol at daily doses of 150 mg is insufficient to guarantee a normuricemic state.