Drug-Herb Interactions (DHI)

Interactions between medications and herbal supplements

Introduction

Herbal supplements and traditional medicines can interact with pharmaceutical drugs. These interactions are often underreported and may be significant in drug repurposing contexts.

Common Interactions

St. John’s Wort

Induces CYP3A4 and P-glycoprotein
Reduces levels of many medications
Examples: oral contraceptives, immunosuppressants, antivirals

Ginkgo Biloba

May increase bleeding risk
Interactions with anticoagulants, antiplatelet drugs
Potential CYP interactions

Ginseng

May affect blood glucose
Potential interactions with diabetes medications
May affect warfarin metabolism

Kava

CNS depressant effects
May enhance sedative medications
Hepatotoxicity concerns

Considerations for Research

When evaluating drug repurposing candidates:

Consider target population herbal supplement use
Evaluate potential pharmacokinetic interactions
Assess pharmacodynamic synergies or antagonisms
Review regional traditional medicine practices