2017 年 43 巻 11 号 p. 630-639
Generic medicines are approved for clinical use without human studies evaluating the effectiveness and side effects. Allopurinol, a xanthine oxidase inhibitor, is often used for the treatment of hyperuricemia and gout, and some of its generic medicines are also approved for use in clinical situations. We retrospectively collected the information about patients with hyperuricemia and gout, who were prescribed only one kind of allopurinol in the first case. We also constructed an indirect response maximum drug inhibitory effect (Imax) model, based on the 634 serum uric acid (UA) levels of 148 patients, and were able to describe the time course of serum UA levels in patients during treatment with allopurinol. Before the initiation of treatment, the basal UA levels were increased in correlation with serum creatinine (SCr) concentrations. The inhibitory effects of allopurinol on the production of UA were attenuated by increase of the body mass index (BMI), but the Imax value differed significantly between males and females. The result of simulation analysis revealed that the achievement rate to decrease serum UA levels below 6.0 mg/dL (until 180 days after the initiation of treatment) was dependent on both the daily dosage of allopurinol and basal UA levels. However, there was no significant difference in anti-hyperuricemic effects of generic and brand-name allopurinol. Collectively, our constructed population pharmacodynamics model could describe the influences of BMI, SCr, and gender on serum UA levels in patients treated with brand-name allopurinol or its generic medicines, but anti-hyperuricemic effects did not differ significantly between brand-name and generic allopurinol.
