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Stanford Chemicals http://www.bestherbalextract.com/

Interaction between Herbal Medicines and Chemical Medicines As a kind of medicine and supplement, plant products tend to be more popular at present. It is estimated that 1/3 people in developed countries choose selective therapies associated with herbal medicine. Herbal medicine is generally used in conjunction with prescription drugs to increase the possibility of the interaction between pharmacokinetics and pharmacodynamics. Clinical researches show that combination drugs could increase or reduce pharmacodynamic effects. Synergistic or additional therapeutic effects may produce toxicity and complicate the dosage regimen of long-term medication, while antagonism may reduce pharmacodynamic effects and lead to treatment failure. Safety issues are worth attention, especially for those medicines with low therapeutic index which may produce side effects and even threat to life. The mechanism that how combined herbal medicines change drug concentration needs to be identified, however, some researches prompt that it may has relations with induction and inhibition of deeply drug metabolic enzymes and drug carriers. There are an increasing number of reports of interaction between herbal medicine and chemical medicine. Such interaction is likely to occur more often than that between chemical medicine and chemical medicine, whose reasons probably include: most patients didn’t reveal facts of using herbal medicine to doctors; herbal medicine is used base on traditional medicine, which is not scientifically pre-clinically and clinically evaluated; lack of good quality control to herbal medicine and unable to fully confirmed the constituent; many countries have no comprehensive supervising systems to monitor adverse reaction of herbal medicine and interaction of herbal medicine and chemical medicine; single herbs include many active constituents, each of which probably contributes to pharmacodynamic effects and drug interactions more or less, so it is more difficult to speculate the interactive mechanisms. As an example, garlic is widely used as an herbal medicine, and it is reported to have antimicrobial function and enhance immunity function. It is often used to improve physical condition of patients infected with HIV and to treat infection. The main bioactive constituent is organic sulfur compounds. It is evaluated recently on the effect of garlic extracts on internal metabolism and excretion of dextromethorphan and alprazolam. External research and animal studies show that effects on enzymatic activities and expression of Cytochrome P450(CYP) depend on the types, chemical constituents and dosage of garlic extracts. Clinical reports show that 2 patients infected with HIV developed severe gastrointestinal toxicity after receiving antiretroviral therapy including ritonavir, who were administrated with garlic extracts for more than 2 weeks. The symptom was subsided after discontinuing garlic extracts or ritonavir. And gastrointestinal symptoms relapsed after given ritonavir with low


Stanford Chemicals http://www.bestherbalextract.com/

dosage again. The reason leading to the toxicity was probably that ritonavir inhibited or induced the metabolism of constituents and produced toxicity of compounds. In addition, constituents of garlic probably inhibited the metabolism of ritonavir mediated by CYP3A or the transportation mediated by P-glycolprotein (P-gp), which resulted in the elevated concentration of ritonavir. Garlic has been used as food additives of patients infected with HIV, so it is necessary to remind patients that there is potential harm for the drug combination of garlic with saquinavir or ritonavir and other protease inhibitor. About Stanford Chemicals Stanford Chemicals is a worldwide supplier of phytochemicals, pharmaceutical intermediates, catalysts, lab equipment and a variety of special fine chemical products since 1994. To meet increasing demands for herbal extracts in nutraceutical, pharmaceutical and cosmetic industries, Stanford Chemicals is established and now carries hundreds kinds of herbal extracts, including botanical ingredients and standard herbal extracts.

Interaction between herbal medicines and chemical medicines  

As a kind of medicine and supplement, plant products tend to be more popular at present. It is estimated that 1/3 people in developed countr...

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