• T89;
  • warfarin;
  • pharmacokinetics;
  • pharmacodynamics;
  • interaction


This open-label, multi-dose, single-center, sequential, inpatient study evaluated the effects of a two herb combination drug (T89, Danshen plus Sanqi) on the steady-state pharmacodynamics (PD) and pharmacokinetics (PK) of warfarin in 24 healthy volunteers. Twenty-three subjects attained a stable international normalized ratio (INR) by taking warfarin alone prior to 1-week of added-on use of T89. INR was not increased after the addition of T89 for 7 days (P > .05). The 90% confidence interval (CI) of the geometric mean ratio for maximum plasma concentrations (Cmax) and area under curve (AUClast) of both R- and S-warfarin when warfarin was administered with or without T89 was within the 0.80 to 1.25 equivalence ratio. These results indicate that T89 has no effect on the steady-state PD and PK of warfarin. Warfarin and T89 dose adjustments are not required when these two drugs are co-administrated in clinical practice.