Which dietary herbal supplement has the highest risk for drug interactions?

Which dietary herbal supplement has the highest risk for drug interactions?

• A. St John’s wort
• B. Echinacea
• C. Garlic
• D. Ginseng

Answer: (A)

Potent enzyme induction leads to many drug interactions. St John’s wort strongly induces hepatic cytochrome P450 enzymes, especially CYP3A4, and also increases P-glycoprotein activity. This speeds up the metabolism and clearance of a wide range of medications, lowering their plasma levels and reducing their effectiveness. Clinically important consequences include reduced effectiveness of birth control pills, various antidepressants and anticonvulsants, immunosuppressants like cyclosporine, and anticoagulants such as warfarin. It can also trigger serotonin syndrome when taken with other serotonergic agents. While echinacea, garlic, and ginseng can interact with drugs in some contexts (for example, garlic’s effect on bleeding risk with anticoagulants), none have as broad or as strong an interaction profile as St John’s wort.

Potent enzyme induction leads to many drug interactions. St John’s wort strongly induces hepatic cytochrome P450 enzymes, especially CYP3A4, and also increases P-glycoprotein activity. This speeds up the metabolism and clearance of a wide range of medications, lowering their plasma levels and reducing their effectiveness. Clinically important consequences include reduced effectiveness of birth control pills, various antidepressants and anticonvulsants, immunosuppressants like cyclosporine, and anticoagulants such as warfarin. It can also trigger serotonin syndrome when taken with other serotonergic agents. While echinacea, garlic, and ginseng can interact with drugs in some contexts (for example, garlic’s effect on bleeding risk with anticoagulants), none have as broad or as strong an interaction profile as St John’s wort.