With the combined use of St. John's Wort preparations with cyclosporine, warfarin, steroid preparations, antiviral agents - reverse transcriptase inhibitors (amprenavir, indinavir, nevirapine, nelfinavir, ritonavir, saquinavir); inhibitors of the activity of proteolytic enzymes may reduce their effectiveness.
The drug is able to enhance the photosensitizing effect of other drugs: tetracyclines, sulfonamides, thiazide diuretics, quinolones, piroxicam, etc.