Herbal Remedies: Drug-Herb Interactions 笔记 part 2
Content:
1. Herbs harmless?
2. STANDARDIZATION AND QUALITY CONTROL
3. DRUG INTERACTIONS
4. DRUG-HERB INTERACTIONS
5. SELECTED POPULAR HERBS
i. Ginkgo (Ginkgo biloba)-----------------------------(Part 1)
2. STANDARDIZATION AND QUALITY CONTROL
3. DRUG INTERACTIONS
4. DRUG-HERB INTERACTIONS
5. SELECTED POPULAR HERBS
i. Ginkgo (Ginkgo biloba)-----------------------------(Part 1)
ii. Flaxseed (Linum usitatissimum)
iii. Feverfew (Tanacetum parthenium)
iv. Ginger (Zingiber officinale)
v. Kava Kava (Piper methysticum)
vi. St John’s Wort (Hypericum perforatum)
6. IMPLICATIONS FOR NURSING
7. Summarizes drug-herb interactions
5. SELECTED POPULAR HERBS
ii. Flaxseed (Linum usitatissimum) 亚麻籽
Flax
- one of the oldest cultivated plants in the world
- grown for its
- fiber (linen)
- seed oil (linseed oil)
- seeds (flaxseed)
- a bulk-producing, stoolsoftening agent that lowers levels of
- cholesterol (9%)
- triglycerides
- low-density lipoproteins (18%)
- flax interferes with the reabsorption of fats by binding to bile acids in the intestinal tract
- When soaked, flaxseeds have mucilaginous properties and can bind with drugs
- especially cardiac glycosides
- rendering them unabsorbable
- Therefore, flaxseed should be taken either 2 hours after or 2 hours before the consumption of other products (drugs, vitamins, and minerals).
- concurrent use of flaxseed with laxatives and stool softeners should be avoided
- because of the possible potentiation of the laxative effect通便功能增加
iii. Feverfew (Tanacetum parthenium)
- most commonly used to reduce the number and the severity of migraine headaches
- has anti-inflammatory activity
- Feverfew suppresses prostaglandin production but does not inhibit cyclooxygenase
- Feverfew inhibits platelet activity
- so it should not be taken concurrently with warfarin or other drugs that affect clotting.
- Feverfew is also a member of the daisy family
- contraindicated in persons with allergy to ragweed.
Prostaglandin production Review: 【Pathology】Pathophysiology of Asthma----Arachidonic acid pathway
iv. Ginger (Zingiber officinale)
- antinauseant and antispasmodic agent 抗恶心和解痉剂
- a potent inhibitor of thromboxane synthetase
- thus prolongs bleeding time
- Therefore, persons taking warfarin or other drugs that affect platelet activity should refrain from taking ginger in tablet form
- Using ginger as a spice is not a problem
v. Kava Kava (Piper methysticum)
- cultivated throughout the South Pacific
- ceremonial drink
- relieves anxiety, nervousness, and tension without affecting alertness.
- acts as a dopamine antagonist
- therefore may increase tremor
- make medications less effective in persons with Parkinson disease.
- also potentiates alcohol, tranquilizers, and antidepressants
- should therefore not be taken concurrently with kava
Antidepressant review: 【Pharmacology】Antidepressants
vi. St John’s Wort (Hypericum perforatum)
- one of the most popular herbs in the United States for the management of depression
- was thought to act as a monoamine oxidase inhibitor
- but this hypothesis has never been confirmed
- Current research suggests that St John’s wort acts as a selective serotonin reuptake inhibitor (SSRI)
- Therefore, concurrent use of SSRIs with St John’s wort is contraindicated.
- Patients should wait at least 2 weeks after taking an SSRI before starting to take St John’s wort, or
- between stopping taking St John’s wort and starting to take an SSRI
- The newest research suggests that St John’s wort may act in the cytochrome P-450 system of the liver
- Concentrations of indinavir were reduced
- a protease inhibitor
- used to treat infection with human immunodeficiency virus
- possibly leading to drug resistance and treatment failure
- Markowitz et al studied the action of St John’s wort on the cytochrome P-450 system in the liver
- their results indicated that St John’s wort was unlikely to inhibit the CYP2D or CYP3A4 liver enzyme systems
- 结论：More research is needed.
- Other researchers today are suggesting that St John’s wort may have an effect like that of grapefruit juice on the metabolism of many drugs
- In another study, transplant recipients who were taking cyclosporine (definitely metabolized in the liver) experienced transplant rejection.
- 结论：Much more research is needed to determine the effect of St John’s wort on the metabolism of other drugs.
- St John’s wort also is associated with photosensitivity
- so other photosensitizing herbs (eg, dong quai) or
- photosensitizing drugs (eg, tetracyclines and chemotherapeutic
- drugs)
- should not be taken concurrently
- Persons taking St John’s wort should be careful about their exposure to sun.
cytochrome P-450 system Review: 【Pharmacology】Antifungal drugs
6. IMPLICATIONS FOR NURSING
- Use of all herbal products should be discontinued 5 to 7 days before surgery. 应在手术前 5 至 7 天停止使用所有草药产品。
- Because pharmacokinetic information on most herbs is not available, how long it takes for most herbal products to be cleared from the body is not known.
- If a patient is having an emergency procedure, nurses should specifically ask about herbs that affect clotting, including
- bromelain
- cayenne pepper
- chamomile
- cinchona bark
- dong quai
- fenugreek
- feverfew
- garlic
- ginger
- ginkgo
- ginseng
- guggul
- horse chestnut
- vitamin E (>1200 IU)
- willow bark
- This information should be discussed with the medical staff.
Patients taking drugs with a narrow therapeutic index
- cyclosporine
- digoxin
- hypoglycemic agents
- lithium, phenytoin
- procainamide
- theophylline
- tricyclic antidepressants
- warfarin
- should be discouraged from using herbal products
- may increased adverse effects
- less effective when used in conjunction with herbal products
7. Summarizes drug-herb interactions
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