Banana juice reduces bioavailability of levodopa preparation.

This study aimed to examine the effects of banana juice on levodopa bioavailability in rats. When a levodopa preparation (EC-Doparl tablets) was orally administered with banana juice made by mixing with a fresh banana and water, there were significant decreases in C(max) (17.4+/-2.5 vs. 8.6+/-3.1 microg/ml; alpha=0.05) and AUC (1882.8+/-49.2 vs. 933.5+/-286.6 microg.min/ml; alpha=0.05) for levodopa. On the other hand, administration of the levodopa preparation with a commercial beverage containing 10% banana juice resulted in no significant change in C(max) or AUC. These results indicate that concomitant intake of levodopa preparations with banana juice, but not with a commercial banana beverage, may cause a drug-food interaction reducing levodopa bioavailability, and we should pay attention to such interactions during levodopa therapy for patients with Parkinson's disease.