Possible Interaction: Digoxin and St John's Wort

“Many medications are known to alter digoxin pharmacokinetics, including the herbal medication St. John's wort.”

“Lastly, multiple herb-drug interactions have been identified with St. John's wort that involve significantly reduced AUC and blood concentrations of warfarin, digoxin , indinavir, theophylline, cyclosporine, tacrolimus, amitriptyline, midazolam, and phenprocoumon.”

“Results from clinical studies and case reports indicate that self-administered SJW reduce steady state plasma concentrations of amitriptyline, cyclosporine, digoxin , fexofenadine, amprenavir, indonavir, lopinavir, ritonavir, saquinavir, benzodiazepines, theophyline, irinotecan, midazolan and warfarin.”

“This is exemplified by increased oral bioavailability of phenytoin and rifampin by piperine and decreased bioavailability of indinavir, tacrolimus, cyclosporine, digoxin , and fexofenadine by coadministered St. John's wort.”

“Recently, St John's Wort was reported to substantially decrease blood/plasma concentrations and efficacy of cyclosporine (INN, ciclosporin), indinavir, and digoxin.”

“Since then, subsequent research has shown that SJW altered the pharmacokinetics of drugs such as digoxin , tacrolimus, indinavir, warfarin, alprazolam, simvastatin, or oral contraceptives.”

“For example, St John's wort significantly reduced the area under the plasma concentration-time curve (AUC) and blood concentrations of cyclosporine, midazolam, tacrolimus, amitriptyline, digoxin , indinavir, warfarin, phenprocoumon and theophylline.”

“Clinical trials indicate …’s wort Hypericum perforatum ), via cytochrome P450 (CYP) and/or P-glycoprotein induction, reduces the …/or increases the clearance) of alprazolam, amitriptyline, atorvastatin, chlorzoxazone, ciclosporin, debrisoquine, digoxin , erythromycin, fexofenadine, gliclazide, imatinib, indinavir, irinotecan, ivabradine, mephenytoin, methadone, midazolam, … contraceptives, quazepam, simvastatin, tacrolimus, talinolol, verapamil, voriconazole and warfarin.”

“Significantly reduced concentrations of various therapeutic drugs such as digoxin , theophylline, cyclosporine, tacrolimus, tricyclic antidepressants, warfarin, and protease inhibitors can be observed due to interaction of these drugs with St. John's wort , causing treatment failure.”

“St John's wort, a popular herbal antidepressant, increases clearance of many drugs, and abnormally low cyclosporine, digoxin , theophylline, or protease inhibitor concentrations may be observed in a patient taking any of these drugs in combination with St John's wort.”