Common Herbal Dietary Supplement-Drug Interactions

Area of Science:

• Pharmacology
• Integrative Medicine
• Clinical Pharmacy

Background:

• Nearly 25% of US adults use prescription medications alongside dietary supplements.
• Certain supplements like St. John's wort can cause significant drug interactions.
• Many predicted interactions are based on in vitro data, not confirmed in humans.

Purpose of the Study:

• To review the potential for drug interactions between common dietary supplements and prescription medications.
• To differentiate supplements with high interaction risks from those with lower risks.
• To guide clinicians in assessing the safety of supplement-drug combinations.

Main Methods:

• Literature review of in vitro and clinical studies on supplement-drug interactions.
• Categorization of supplements based on their likelihood of causing clinically significant interactions.
• Analysis of factors influencing supplement-drug interactions.

Main Results:

• Some supplements (e.g., St. John's wort) pose high interaction risks.
• Many supplements have low interaction potential or interactions are unconfirmed in humans.
• Specific supplements like curcumin, echinacea, garlic, and green tea may interact with certain drugs but are often safe.
• Supplements like black cohosh, cranberry, ginkgo, and milk thistle generally have a low likelihood of interactions.

Conclusions:

• Clinicians must assess individual supplement-drug combinations using reliable resources.
• Encouraging open patient disclosure of supplement use is crucial for safety.
• Building trusting patient relationships facilitates the detection of potential herb-drug interactions.