Impact of ginkgo biloba on the pharmacokinetics of digoxin.

Abstract

Many medications are known to alter digoxin pharmacokinetics, including the herbal medication St. John's wort. An open-labeled, randomized, crossover trial was conducted in eight healthy human volunteers to determine if ginkgo biloba (GB) also alters the pharmacokinetics of digoxin. On two occasions separated by 2 weeks, subjects ingested digoxin, 0.5 mg. One week prior to each study phase, half of the volunteers were randomly initiated on GB therapy, 80 mg three times daily, that continued until the end of the study phase. Immediately prior to and for 36 hours following digoxin ingestion, multiple blood samples were collected for digoxin plasma concentration determination. No significant difference between treatments was observed with respect to AUC(0- infinity ) (digoxin alone: 21.0 +/- 8.6 [ng/mL] x h; digoxin + GB: 25.6 +/- 13.2 [ng/mL] x h). Additionally, no significant difference between therapies was observed with respect to C(max), T(max), or Cl(o). In six subjects, k(e) and t(1/2) were able to be determined. These parameters also did not differ significantly between treatments. In conclusion, within the context of the specific GB product used during this investigation, the concomitant use of GB and digoxin did not appear to have any significant effect on the pharmacokinetics of orally administered digoxin in healthy volunteers.