Herb – Drug Interactions

Question 1

Bai Mao Liang (Goldenseal)

Answer 1

Warfarin, Heparin: Increases risk of thrombo-embolism

Question 2

Ju Hua

Answer 2

Barbiturates Intensify or prolong effects of sedatives

Iron supplements Reduces iron absorption

Warfarin Increases bleeding

Question 3

Echinacea

Answer 3

Immunosuppresants: Stimulates T-cells, antagonist to immunosuppressant drugs.

Amiodarone, anabolic steroids, ketoconazole, methotrexate:
Slows metabolism of drugs, increases hepatotoxicity

Question 4

Ma Huang

Answer 4

Epinephrine, pseudophedrine,
phenylpropanolamine: Increases stimulating effects

MAOI: Intensifies effect of medication and side effects (stomachache,
headache, tremors, hypertension)

Question 5

Xiao Bai Ju (Feverfew)

Answer 5

Antimigraine (ergotamine) increases stimulating effect of medication
Antiplatelet Increases bleeding
Iron supplements Reduces iron absorption
NSAIDs Prevents migraine medication effect
Warfarin Increases bleeding

Question 6

Da Suan (Garlic)

Answer 6

(Cardiac meds)
Warfarin: Increases bleeding

Antihypertensive :Augments antihypertensive effect

Antiplatelet drugs: Increases bleeding

Protease inhibitors: Reduces protease effect

Question 7

Sheng Jiang (Ginger)

Answer 7

Antiplatelet drugs: Increases bleeding

Warfarin: Increases bleeding

Question 8

Bai Guo and Yin Xing

Gingko

Answer 8

Anticonvulsants (phenytoin): Reduces efficacy
MAOI (tranylcypromine): Intensifies side effects (headache, tremors, manic episodes)
NSAIDs: Increases bleeding
Warfarin: Increases bleeding

Question 9

Ren Shen (Ginseng)

Answer 9

Antihyperglycemic (glipizide): Increases hypoglycemia

Aspirin (NSAIDs): Increases bleeding

Corticosteroids: Increases adverse effects of anti-inflammatories

Digoxin: Increases digoxin levels

Estrogen: Intensify adverse effects

MAOIs: Headache, Tremors, Manic episodes

Opioids: Reduce effectiveness

Warfarin: Increases bleeding

Question 10

Lu Cha (Green Tea)

Answer 10

Decreased iron absorption

Warfarin: Increases thromboembolism

Question 11

Kava

Answer 11

Sedatives (Barbiturates, benzodiazepines): Intensify or prolong sedatives

Question 12

Gan Cao (Licorice)

Answer 12

Anti-arrhythmic: Increases abnormal heart rhythm

Antihypertensives:
Increases blood pressure (due to increase of sodium and water retention)

Digoxin: Decreases K+, increases digoxin toxicity

Diuretics: Increases K+ wasting

MAOIs: Increases side effects: headache, tremors, manic episodes

Question 13

Milk Thistle

Answer 13

Antihyperglycemics: Intensifies hypoglycemia
Protease inhibitors (indinavir, saquinavir): Interferes with metabolizing enzymes, lowers blood levels

Question 14

Saw palmetto

Answer 14

Estrogen (oral contraceptives): Augments effectiveness
Warfarin
Protease inhibitors

Question 15

Guan Ye Lian Qiao

St. John’s Wort

Answer 15

Cyclosporine: reduces function

Digoxin: Increases toxicity of digoxin, reduces effectiveness

Iron supplements: Reduces iron absorption

MAOIs: Augments MAOIs, can cause traumatic hypertension (ER referral)

Non-Nucleoside reverse transcriptase
inhibitors: Increases metabolism of drugs, reduce effectiveness

Oral contraceptives: Increases metabolism of drugs, reduces effectiveness

Photosensitizing medication: Increases photosensitivity

Protease inhibitors: Reduces blood level and efficacy

SSRIs: Augments effects of drugs

Tricyclic antidepressants: Augments effects of medication

Question 16

Xie Cao (Valerian)

Answer 16

Barbiturates, benzodiazepines: Intensifies sedatives