What products contain St. John's Wort, grapefruit, or ginkgo that may interact with medications such as blood thinners, diabetes medications, or certain antidepressants?

Common Products Containing St. John's Wort, Grapefruit, and Ginkgo

Patients frequently consume these ingredients unknowingly in dietary supplements, herbal teas, beverages, and over-the-counter products, making it essential to specifically ask about these hidden sources during medication reconciliation. 1

St. John's Wort Hidden Sources

Dietary Supplements and Herbal Products

• Mood and stress supplements often contain St. John's wort without prominent labeling, marketed under names like "mood support," "stress relief," or "emotional wellness" formulas 1
• Sleep aid combinations frequently include St. John's wort mixed with valerian, melatonin, or other sedatives 2
• Menopause symptom relief products commonly contain St. John's wort as an ingredient for mood stabilization 3

Herbal Teas and Beverages

• Herbal tea blends marketed for relaxation or mood enhancement may contain St. John's wort, often listed as "Hypericum perforatum" on ingredient labels 4
• Wellness teas combining multiple herbs for "emotional balance" frequently include St. John's wort 5

Critical Drug Interactions

• St. John's wort induces CYP3A4 and P-glycoprotein, reducing effectiveness of warfarin, oral contraceptives, SSRIs, HIV protease inhibitors, immunosuppressants (cyclosporine, tacrolimus), statins, digoxin, and anticonvulsants 1, 4
• The American Society of Anesthesiologists recommends discontinuing St. John's wort at least 2 weeks before surgery due to multiple drug interactions 1

Grapefruit Hidden Sources

Beverages and Juices

• Fruit juice blends containing grapefruit, even in small amounts, can cause significant CYP3A4 inhibition 3
• Citrus-flavored drinks and "tropical" juice combinations often include grapefruit juice without prominent labeling 6
• Cocktail mixers and alcoholic beverages may contain grapefruit juice 7

Food Products

• Marmalades and preserves made with grapefruit 7
• Fruit salads and pre-packaged fruit cups frequently contain grapefruit segments 7
• Salad dressings with citrus flavoring may include grapefruit 7

Critical Drug Interactions

• Grapefruit juice inhibits intestinal CYP3A4, dramatically increasing levels of statins (atorvastatin, lovastatin, simvastatin), certain calcium channel blockers, and immunosuppressants 3
• The American Heart Association notes grapefruit affects losartan metabolism and recommends patients maintain consistent consumption patterns if they regularly consume grapefruit products 6
• For warfarin patients, grapefruit juice should be limited to no more than 200 mL (7 ounces) per day 7

Ginkgo (Ginkgo Biloba) Hidden Sources

Dietary Supplements

• Memory and cognitive enhancement supplements are the most common source, often marketed for "brain health" or "mental clarity" 8, 2
• Multi-ingredient "senior" vitamins frequently include ginkgo biloba 3
• Energy supplements and "focus" formulas commonly contain ginkgo 2

Herbal Combinations

• Circulation support products often combine ginkgo with other herbs 5
• Tinnitus relief supplements frequently list ginkgo as a primary ingredient 8

Critical Drug Interactions

• Ginkgo biloba has been reported to cause spontaneous bleeding and may interact with anticoagulants (warfarin) and antiplatelet agents (aspirin, clopidogrel) 8, 9
• The five most common natural products with potential for clinically significant interactions—garlic, valerian, kava, ginkgo, and St. John's wort—accounted for 68% of all potential interactions in a Mayo Clinic study 2

Clinical Management Strategies

Patient Screening Questions

• Ask specifically about: "Do you take any supplements for mood, memory, sleep, or stress?" 1
• Ask about beverages: "Do you drink grapefruit juice, citrus blends, or herbal teas?" 6, 7
• Review all over-the-counter products: Many patients don't consider supplements as "real medicine" and fail to report them 3

High-Risk Medication Classes Requiring Vigilance

• Antithrombotic medications (warfarin, antiplatelet agents) with ginkgo or grapefruit 7, 9, 2
• Antidepressants (SSRIs, MAOIs) with St. John's wort—risk of serotonin syndrome 1, 4
• Antidiabetic agents with various herbal supplements 2
• Immunosuppressants (cyclosporine, tacrolimus) with St. John's wort or grapefruit 1, 4

Documentation and Monitoring

• The American Academy of Pediatrics recommends obtaining a complete herbal supplement history and monitoring patients more frequently when interactions are identified 1
• Between 31% to 68% of cancer patients using supplements don't discuss this with physicians, highlighting the need for direct questioning 3