Drug Interactions between digitoxin and ginseng

GENERALLY AVOID: Asian and Siberian ginseng may interfere with digoxin either pharmacodynamically or with its monitoring via certain immunoassays. The interaction has been observed in vitro as well as in nondigoxin-treated mice that were fed ginseng and is thought to be due to substances in the ginseng that structurally resemble cardiac glycosides. Serum pools prepared from samples from patients receiving digoxin and then supplemented with Asian or Siberian ginseng also demonstrated interference. In one case report, a 74-year-old man who had been taking a constant dose of digoxin for many years was found during a routine office visit to have unexplained elevated serum digoxin level with no clinical signs of toxicity. The level remained high even after stopping the drug, whereupon the patient revealed that he had been taking a Siberian ginseng capsule. Soon after discontinuation of the capsules, serum digoxin returned to an acceptable level and therapy was resumed. Digoxin level again rose several months later when the patient resumed taking the ginseng but fell to within therapeutic range shortly after he stopped, despite continued therapy with digoxin at the same dosage. No analysis was performed to determine whether the capsules actually contained Siberian ginseng and if so, at what concentration.

MANAGEMENT: Patients should consult a healthcare provider before taking any herbal or alternative medicine. Use of ginseng should probably be avoided in patients treated with cardiac glycosides.