Marked decrease of tacrolimus blood concentration caused by compound Chinese herbal granules in a patient with refractory nephrotic syndrome.

What Is Known And Objective: The blood concentration of tacrolimus can be affected by co-administrated drugs. The objective is to draw more attention to herb-drug interactions in China, where herbal medicines are commonly used.

Case Description: The blood concentration of tacrolimus in a girl with refractory nephrotic syndrome decreased nearly a half despite no change in dose. Nebulizer therapy, cyclophosphamide and a compound Chinese herbal medicine were the only additional treatments than usual.

What Is New And Conclusion: The most possible cause of the decrease in tacrolimus concentration was the administration of Radix Astragali among compound Chinese herbal medicine granules.