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Drug-herb Interaction
CuiHan
Handouts
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The interactions of herbs and drugs
Recognition and prevention of herbdrug interaction
Warfarin and chinese medicine
Herb to herb interactions
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Mutual accentuation (Xiang Xu): The combination of two
substances with similar functions accentuates their therapeutic
actions.
Mutual enhancement/assistance/employment (Xiang Shi): The
combination of herbs with different actions in which one of the
substances enhances the effect of the other in a specific clinical
situation.
Mutual counteraction/restraint/fear (Xiang Wei):A combination
in which the toxicity or side effects of one substance are
reduced or eliminated by another substance.
Mutual suppression/killing (Xiang Sha)
Mutual antagonism/aversion (Xiang Wu): The ability of two
substances to minimize or neutralize each other’s positive
effects.
Herb to herb interactions
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Mutual incompatibility / opposition (Xiang
Fan): The combination of two substances
gives rise to side effects or toxicity which
would not be caused by either substance
when used alone.
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Eighteen herbs of mutual incompatibility
(Shi Ba Fan)
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Gan Cao---Gan Sui, Da Ji, Yuan Hua and Hai Zao;
Wu Tou----Bei Mu, Ban Xia, Gua Lou, Bai Lian, Bai Ji
Li Lu--------Ren Shen, Sha Shen, Dan Shen, Xuan
Shen, Xi Xin, Shao Yao.
Herb to drug interactions
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Herbs with drugs for hypertension, seizures, diabetes, thyroid
conditions
Diuretic herbs and diuretic drugs may have additive or
synergistic effects, making hypertension more difficult to control:
Fu ling, zhu ling, che qian zi, ze xie
Anticoagulant drugs and herbs of blood activating and blood
stasis removing function: warfarin and Dan shen, Dan shen,
chuan xiong, shui zhi, tao ren, hong hua
Anti-diabetic herbs may interfere with anti-diabetic drugs by
enhancing hypoglycemic effects: zhi mu, shi gao, xuan shen,
cang zhu, shan yao, huang qi
Teratogenic herbs
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Teratogenic herbs are known to have the tendency of
causing danger or harm to the fetus during
pregnancy and thus leading to birth-defects or
spontaneous abortion.
Prohibited herbs: qian niu zi, da ji, ban mao, shang lu,
she xiang, e zhu, shui zhi, meng chong
Herbs that should be used with caution are herbs
that are pungent and warm in nature and have the
functions to activate qi, activate blood circulation and
remove blood stasis: tao ren, hong hua, da huang,
zhi shi, fu zi, rou gui, gan jiang
The interaction of drugs and herbs
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Adverse effects of combining grapefruit juice with
drugs for calcium antagonists (lower blood pressure),
the benzodiazepines midazolam and triazolam (for
depression), and terfendadine (for allergies) are due
to the greatly increased amount of drug in the
bloodstream due to inhibited drug metabolism.
Zhi shi, zhi ke, ju he, qiang huo, du huo, dang gui, bu
gu zhi
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Some herbs can increase drug
metabolism rather than decrease it,
resulting in lower drug availability.
St. John’s wort in AIDS treatment
Monoamine oxidase inhibitors (MAOIs)
and Essence restoring herbs
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He shou wu, shu di huang, sha yuan zi,
tu si zi, lu rong
Effects of low levels of monoamines are
depression and hypertension. There is
an increase in MAO activity with aging.
Those herbs reduce the MAO level and
activity
Tetracycline and milk
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The interaction with milk is an
interaction with calcium in the milk.
Inhibition of the drug’s absorption can
also occur when taking any mineral rich
food or herb, such as oyster shell,
dragon bone, gypsum, mother of pearl.
Ginger
Blood thinners and green
vegetables
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Vitamin K has coagulation promoting
qualities that overcome the
anticoagulant drug.
Dang gui, Dan shen enhance the
warfarin effects.
Steroids and chinese herbs
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Many herbs can enhance the circulating levels of corticosteroids
by slowing their metabolism.
Enhanced levels of sex hormones in aged individuals may be
one of the mechanisms by which antiaging chinese herbs are
able to improve patient condition.
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Chinese herbs serve as a replacement for the corticosteroid
therapy in the treatment of rheumatoid arthritis, viral hepatitis,
and enphritis. Fu ling, zhu ling, cang zhu, gui zhi, gan cao.