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Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

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Page 1: Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

Herb-Drug Interactions

“Concurrent use of herbs may mimic, magnify, or oppose the

effect of drugs”

Page 2: Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

Numbers of Herb-Drug Interactions Reported by Various Sources

Source # of herbs described

# of herbs

w/interactions

Botanical Safety Handbook 540 11Herb Contraindications and Drug Interactions

207 79*

British Herbal Compendium 84 17ESCOP Monographs on the Medicinal Use of Plant Drugs

60 15

The Complete German Commission E Monographs

308 35

Herbal Medicines-A Guide for Health-Care Professionals

107 42

WHO Monographs on Selected Medicinal Plants

28 14

Herbal Medicines-A Guide for Health-Care Professionals

141 ---†

Mechanisms of Drug Interactions

NA 55‡

HealthNotes Clinical Essentials

151 48

Page 3: Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

Types of Herb-Drug Interactions

Type of Interaction # of Herbs

Modifies intestinal absorption of medicines

Impairment by hydrocolloidal fiber 23

Selective precipitation of drug by tannins 38

Selective precipitation of drug by iodine 12

Enhancement of drug by pungent herbs 4

Potentiates cardiotonic medicines

Herbal cardiotonics 11

Stimulant laxatives 17

Enhancers of urinary potassium excretion 8

Potentiates sedative or tranquilizing 21

medications

Modifies blood sugar in insulin-dependent diabetes

Hypoglycemic herbs 72

Hyperglycemic herbs 9

Modifies effects of prothrombopenic anticoagulants

Potentiation by coumarin-containing plants 7

Potentiation by platelet aggregation inhibitors 11

Antagonism by plants high in vitamin K 18

Incompatible w/medications for gastrointestinal tract

Stimulants for secretion of stomach acid 37

Page 4: Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

Potential Severity of Herb-Drug Interactions

Severity of Interaction

# (and %) of Interactions

Beneficial effects or reduction of drug side effects

18 (17.0)

Innocuous effects 28 (26.4)

Production of disease or enhancement of side effects

18 (17.0)

Threat to life through interaction with dangerous drugs

42 (39.6)

Total 106 (100 %)

Page 5: Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

Potentially Serious Herb-Drug Interactions

Type of Interaction # of Herbs

Affects absorption of drugs 17

Enhances potassium loss if given with diuretics

5

Interacts with monoamine oxidase inhibitors

11

Interacts with cardiac glycosides

12

Enhances effects of barbiturates

10

Alters effects of blood sugar medications

9

Interacts with anticoagulant medications

9

Page 6: Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

Herb-Drug Interactions“Evidence that it Occurs”

(2,000 Study)

No. and % of

Type of study interactions

Animal trials 28 19.5

Speculative 27 18.9

Empirical 26 18.2

Human case reports 15 10.5

Human clinical trials 11 25.2

Human studies 36 7.7

TOTAL 143

Page 7: Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

Herb-Drug Interactions(Some Examples)

• Bleeding when warfarin is combined with ginkgo or garlic

• Mild serotonin syndrome when S.J.W. is taken with serotonin re-uptake inhibitors

• Decreased bioavailability digoxin and cyclosporin when S.J.W. is consumed

• Induction of mania in depressed patients with neoleptic drugs; are taken with betel nut (Areca sp.)

• Increased risk of hypertension when tricyclic antidepressants are combined with yohimbine

• High soluble fiber plants such as psyllium decreases drug absorptions

Page 8: Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

Herb-Drug Interactions“10 herbs you can trust”

• Bilberry (Vaccinium sp.) for night blindness, simple diarrhea, glaucoma and cataracts

• Echinaceae for colds, flu and respiratory infections

• Feverfew (Tonacetum sp.) to prevent migraines

• Ginger (Zingiber sp.) for motion sickness, indigestion

• Ginkgo to improve memory – avoid with blood thinners

• Hawthorne (Cratagus sp.) reduce high blood pressure, treat congestive heart failure

• Milk Thistle (Silybum sp.) to treat liver disease

• Saw palmetto (Serenae) to increase urine flow

• Saint John’s Wort (Hypercium sp.) for mild depression

• Valerian (Valeriana sp.) for insomnia and restlessness

* American Botanical Council and based on the German Commission E. monographs.

Page 9: Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

Herb-Drug Interactions“The Dirty Dozen”

Category 1: “Definitely hazardous”

a. Aristolochic acid (Aristolochia sp.) 1993: 30 cases of kidney failure among Belgian women using powered Chinese herbs (weight control) which was adulturated with Aristolochia sp.2002: 237 of nephropathy is Asia and Europe after prolonged use of Chinese herbs for increased athletic performance. Product was contaminated with aristolochic acid. (aristolochic acid is metabolically activated to carcinogen compounds by cytochrome P450)

b. Germander (Teucrium sp.)1990’s in France: 26 cases of hepatic toxicity after 9 weeks use of germander for weight and cholesterol reduction.- jaundice disappears within 8 weeks discontinued use but returned “promptly” after re-use started- the furano diterpenoids in germander causes reduction in glutathione (reversed with cystine)

* Alternative Medicine Alert Vol. 7: 2004 and Consumer Reports May 4, 2004

Page 10: Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

Herb-Drug Interactions “The Dirty Dozen”

Category 2: “Potentially hazardous with prolonged internal use

a. Comfrey (Symphytum sp.) – contains pyrrolizidine alkaloids which are hepatotoxins. Concentration is 100x higher in roots than aerial parts. Primary use: as a tea, but has been used long-term (safely) in the form of powdered root for external treatment of insect bites, sprains, inflammations and bruises.

b. Chaparrel (Larrea sp.) – long-term use as a external anti-inflammatory but if used internally can cause non-fatal kidney/liver damage. Since 1969, when it was reported to cause remission of melanoma, the use of chaparrel in tea has been widespread yet few adverse case reports except where other herbs have been used.

c. Kava (Piper sp.) – popular use as a relaxant but in 2002 FDA issued a warning about its association with liver toxicity. In 2003, Kava was banned in Germany. It’s toxicity has not been established so care in its use should be standard procedure.

d. Androstenedione – a non-herb supplement derived from animal adrenal glands and gonads. It is used in conjunction with some herbs as a testosterone precursor to enhance muscle development. Currently banned by most amateur / athletic organizations. Short-term use has little or no side effects but evidence of increased cancer rates with long-term usage.

Page 11: Herb-Drug Interactions “Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs”

Herb-Drug Interactions“The Dirty Dozen”

Category 3: Hazardous with acute excessive dosage”

a. Pennyroyal oil (Hedeoma sp.) excessive use of the volatile oil to treat colds should be avoided such at high level as it is a hepatoxic/nephrotoxic compound. In the 1980’s reports of women taking toxic levels of pennyroyal oil to induce abortion but not effective.

b. Yohimbine (Pausinystalia sp.) has been marketed for 80 years to treat impotence. Potential toxicity: hypertension, anxiety, dizziness but rarely death.

c. Lobelia (Lobelia sp.) widely used in American herbalism as a expectorant. Potential toxicity: nausea, vomiting, arrhythmias and rarely death; often used with other herbals as a muscle relaxant (external) or internally to treat respiratory problems.

d. Bitter orange (Citrus sp.) – the Seville orange popular in some areas of South America for insomnia, anxiety and epilepsy. Also, becoming popular as a anti-obesity agent. Since the amines present apparently increase lipolysis and fat oxidation in mammalian fat cells. Concern is with occurrence of arrithymias in obese people use bitter orange formulations