Which herb reduces the effects of certain calcium channel blockers?

Which herb reduces the effects of certain calcium channel blockers?

• A. Ginkgo biloba
• B. Valerian
• C. St. John's wort
• D. Echinacea

Answer: (C)

This hinges on an herb-drug interaction caused by enzyme induction that speeds up how quickly a drug is metabolized. St. John’s wort can induce liver enzymes (primarily CYP3A4) and P-glycoprotein, which increases the breakdown and clearance of many medications, including calcium channel blockers. When these blockers are metabolized faster, their blood levels drop, making them less effective at lowering blood pressure or relieving angina. So the herb can blunt the therapeutic effects of calcium channel blockers. Ginkgo biloba, valerian, and Echinacea have different interaction profiles (such as bleeding risk with anticoagulants, sedative effects, or immune-related effects) and do not typically produce the same reduction in calcium channel blocker efficacy via enzyme induction. If someone is on a calcium channel blocker, it’s important to consult a clinician before starting St. John’s wort, as dosing may need adjustment or an alternative therapy might be appropriate.

This hinges on an herb-drug interaction caused by enzyme induction that speeds up how quickly a drug is metabolized. St. John’s wort can induce liver enzymes (primarily CYP3A4) and P-glycoprotein, which increases the breakdown and clearance of many medications, including calcium channel blockers. When these blockers are metabolized faster, their blood levels drop, making them less effective at lowering blood pressure or relieving angina. So the herb can blunt the therapeutic effects of calcium channel blockers.

Ginkgo biloba, valerian, and Echinacea have different interaction profiles (such as bleeding risk with anticoagulants, sedative effects, or immune-related effects) and do not typically produce the same reduction in calcium channel blocker efficacy via enzyme induction. If someone is on a calcium channel blocker, it’s important to consult a clinician before starting St. John’s wort, as dosing may need adjustment or an alternative therapy might be appropriate.