Herbs interactions with drugs

TABLE 4.1 (CONTINUED) Herbs Interacting with Drugs... 

Interaction with drug metabolism liquorices, which are the most commonly used herbs in TCM can increase metabolites (e.g., nortriptyline, desipramine, and norclomipramine) of tricyclic antidepressants (TCAs) and may produce more side effects (such as dry mouth, constipation, palpitation, etc.) (Xu, 2004 Zhu Huang, 2004). 

To make a rational decision about a herbal product, it would be necessary to know what it contains, whether it is safe, how it interacts with drugs or other herbs, and whether it has been demonstrated to be as good or better than pharmaceutical products available for the same purpose. For most herbal ingredients this information is incomplete or unavailable. 

Although most botanical products are probably safe under most conditions, some are known to be toxic at high doses and others may have potentially adverse effects under some conditions. Many dangerous and lethal side effects have been reported from the use of herbal products. These side effects may occur through several different mechanisms, including direct toxic effects of the herb, effects of contaminants, and interactions with drugs or other herbs. 

Milk thistle appears to be remarkably safe, with loose stools due to increased bile solubility and occasional allergic reactions being the common side effects. It has not been evaluated in children or in pregnant women. There are no known serious drug or herb interactions. 

Patients with cardiovascular disease (including hypertension), diabetes (risk of hyperglycemia), pregnancy (uterine contractions), prostatism, and anxiety disorders are among those who should not take ma huang at any dose. Drug-herb interactions occur with MAOIs (hypertensive crisis), phenoth-iazines (tachycardia, hypotension), (3-blockers (hypertension) and theophylline (increased CNS effects). Of course, caffeine and other stimulants have an additive effect. 

Many dozens of herbal supplements are available to be purchased over-the-counter. Discussion of all these herbal supplements is beyond the scope of this article. Listed below is a brief discussion of each of the more commonly available and used supplements, including highlights of known active constituents, pharmacology, dosing, supporting clinical literature, adverse effects, and interactions with conventional medications. The known and potential drug-herb interactions are summarized in Table... 

Ephedra has been closely linked to methamphetamine production. There are movements In many localities to outlaw the herb. There are many drug interactions with Ma huang. )9-BI(K kcrs may enhance the sympathetic effect and cause hypertentiion. MAOIs may interact with ephedra to cause hypertensive cri.si.s. Phcnothiaz.ines might block the or effects of ephedra, causing hypotension and tachycardia. Simultaneous use of theophylline may cau.se GI and CNS effects. In pregnancy, ephedra is absolutely contraindicated (uterine stimulation). Persons with heart disease, hypertension, and diabetes should not take ephedra. 

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