Shensong Yangxin Capsules Reduced INR in Two Cases and Literature Review

OBJECTIVE To explore the effect of drugs containing ginseng on warfarin as well as the mechanism of interaction and strategy for the interaction management. METHODS Case review was used, a 62-year-old woman with non-valvular atrial fibrillation initiated warfarin therapy and then the international normalized ratio (INR) achieved therapeutic range. After the addition of Shensongyangxin capsules for 4 d, INR value fell to 1.68. Then the INR value rose abrove 2 after stopping Shensongyangxin capsules for 4 d. Another 57-year-old man with non-valve atrial fibrillation who has been stable on warfarin therapy (4.0 mg·d^-1) experienced INR value 1.56, then warfarin dose was adjusted to 4.5 mg·d^-1 and the INR value rose abrove 2.0. RESULTS The addition of Shensongyangxin capsules which contains ginseng on stable and therapeutic warfarin might reduce the effect of warfarin. It was possible that ginseng modestly induced CYP2C9, but other potential mechanisms such as the inhibitory on platelets had not been ruled out. CONCLUSION Patients on warfarin therapy shall avoid taking any ginseng products. The patient shall be advised to monitor INR value and adjust the doses based on INR value monitoring if continue taking ginseng.