St John’s Wort and Related Drug Interactions: A Review

Introduction: St John’swort (HypericumperforatumL.) is a perennial plant that has transparent perforations on its leaves. It has been used as medicinal herb since ancient time. Medicinal values:Many bioactive compounds have been isolated fromSt John’swort. Among those compounds hypericin and hyperforin are well studied. Both have antidepressant effects. This herb has also antineoplastic, antiviral and many other effects. Oil macerates are also used in wound healing. St John’s wort extracts are used as complementary medicine in many countries. Pharmacology: Few studies suggests that it inhibitsmonoamine oxidase and re-uptake of serotonin, dopamine and norepinephrine. But it causes induction of liver cytochrome oxidase enzymes and also causesmany adverse effects including mania and photosensitivity. Drug interactions:Most of the drug interactions occur due to its enzyme induction properties. It can also reduce plasma concentration of antidepressants like amitriptyline and SSRI. It increases serotonergic effects of antidepressants such as duloxetine and venlafaxine. Data suggests that it has significant interactions with antiepileptics, combined oral contraceptives, calcium channel blockers, lipid regulating drugs (statins), antivirals and many more. Conclusion: Although most popular use of St John’s wort is mild to moderate depression, it should be taken under supervision of physician as many cases its concomitant uses are not advisable. KEY WORDS: St John’s wort, Drug interactions.