Impairment of absorption of digoxin by acarbose

This study was conducted to determine the effect of acarbose on serum concentrations of digoxin in healthy male volunteers. A randomized crossover design with three phases was used. In phase 1 participants received 0.5 mg of digoxin alone. In phase 2 they received 0.5 mg of digoxin 0.5 hours after a 200-mg dose of acarbose. In phase 3 they received 100 mg of acarbose 0.5 hours before each meal three times daily for 3 days. On the fourth day, they received 0.5 mg of digoxin 0.5 hours after a 100-mg dose of acarbose. Area under the concentration-time curve (AUC0-48) and mean maximum concentration (Cmax) were significantly lower and tmax significantly increased in phases 2 and 3 compared with phase 1. These results indicate that the absorption of digoxin is reduced by administration of acarbose, and that one of the major mechanisms of this interaction may be due to the pharmacodynamics of acarbose.