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Books and Articles by Dr. Ranvir Pahwa


Ranvir Pahwa

Since time immemorial different medical systems have been integrated. Several systems of Complementary and Alternative Medicine (CAM) integrate herbs and drugs successfully. Herbs are pharmacologically active natural products and are often taken with drugs. The chances of interactions are very likely. This article provides information about the integration of herbs with drugs.

The modalities of modern medicine have resulted in several adverse and toxic side effects. Do we practice "Do no harm" medicine? Ayurveda recommended this before any other system of medicine. People are now detouring from modern medicine to find a safer system. Herbs and other CAM modalities have made a comeback, along with many new sciences. Some of the reasons that prompted people to look for alternatives are:

(a) Unwanted side effects of drugs

(b) Inability to manage chronic ailments

(c) Surgery was not always successful in improving health condition

(d) Several research studies have proven that CAM modalities are safe and effective

(e) Inclination toward self-healthcare; improvement in diet and lifestyle.

Patients are taking herbs along with drugs because herbs are safer and generally do not have toxic side effects. There is a dilemma among practitioners as to whether integrated medicine is safe or not. However, many physicians are cooperating with patients who use these modalities and an increasing number of physicians want to learn about CAM.For many health problems patients prefer herbs because they provide benefits that drugs do not, while for other health conditions patients depend on prescription drugs as the only source of relief. Herbs and drugs can be taken together for certain health problems, but caution should be exercised when integrating herbs and drugs, just as caution is required when taking two or more drugs together. There is a lack of research on the interaction of drugs and herbs. Understanding the pharmacology of drugs and herbs and the mechanisms by which their interactions proceed can assist in predicting or allowing early recognition of drugherb interactions. It is a vast area but certain issues and concerns must be addressed. The interactions of herbs and drugs can be categorized as follows:

(a) Positive interactions: Herbs supporting drug functions

(b) Adverse drug interactions

(c) No interactions

Some common examples of herb-drug interactions are discussed below.

Anticoagulant effects: Butchers broom, feverfew, alfalfa, sweet clover, chamomile, cayenne, licorice, dong quai, garlic, ginger, ginseng, gingko biloba, and kava kava show an anticoagulant effect. Dosage adjustment and monitoring of coagulation time are needed when anticoagulant drugs are taken along with these herbs.

Anticoagulants can also alter the transport of medicine due to low viscosity of the blood. This can hasten the elimination time or increase the toxic effects of herbs and drugs on the organs and organ systems.

Cardiovascular effects: Hawthorn can be used in mild cardiac insufficiency, mild forms of bradycardial arrythmias, and to regulate blood pressure. Arjuna, an Ayurvedic herb, has also been reported as good for treating heart conditions. It is used as a cardiac tonic and for cardiac failure and dropsy. It also relieves hypertension. Use caution when taking these herbs in conjunction with drugs for cardiac conditions.

Ginseng may interfere with the action of digoxin. St. John’s wort may increase blood pressure and cause confusion and drowsiness. Black cohosh may decrease blood pressure.

Diuretic effects: The following herbs possess diuretic action: berberis, corn silk, couch grass, dandelion, horsetail, parsley, juniper berry, and uva-ursi. Dosages of diuretic drugs should be adjusted when these herbs are taken. In addition to diuretic properties these herbs have other benefits for which patients are inclined to take them. For example, parsley is nutritive, dandelion is a liver tonic, juniper berry and uva-ursi are anti-infective, and corn silk helps treat incontinence.

Estrogenic activity: Use of estrogenic herbs such as black cohosh, dong quai, chaste berry, red clover, and wild yam should be monitored in patients taking hormone replacement therapy drugs.

Anti-cold and Anti-cough medicines: Herbal and aromatic oils are sometimes incorporated into cold and cough medicines. Recently the herb Echinacea has been incorporated into over-the-counter cough syrup. Echinacea boosts the immune system and is reported to increase T- and B-lymphocytes. It may have positive effects after chemotherapy also. Echinacea may show adverse effects in patients with autoimmune disorders and it may negate the effects of immunosuppressants such as cyclosporine.


(a) Patients undergoing surgery have possible risks if taking the herbs mentioned above that affect coagulation time

and blood pressure. In addition, licorice may cause hypokalemia.

(b) Uva-ursi may interfere with the absorption of several alka loid drugs.

(c) Tannic acids in St. John’s wort and Saw Palmetto may inhibit iron absorption, undermining the benefits of prescribed anemia drugs.

(d) Ginseng may cause headaches, tremulousness, and manic episodes if taken with the antidepressant phenelzine sulfate.

(e) Milk thistle has been reported to reduce and prevent toxic side effects in the liver caused by drugs.

There are no reports of adverse interactions for many herbs, however caution should still be exercised. Caution should also be exercised in prescribing herbs during pregnancy.

Other valuable suggestions:

(a) Do liver and/or kidney function tests before, during, and after the use of herbs to check for any toxicity.

(b) Herbal energetics: Western herbal formulas are not based on the energy principles of combining herbs as inAyurvedic and Chinese medicine. Combining herbs without the knowledge of their energy can lead to toxic side effects. Recently a formula for postmenopausal syndrome that contained all the available estrogenic herbs caused severe diarrhea (personal communication).

(c) It is important to know that herbs can interact with other herbs in the same way that drugs can interact with other drugs. The chance of interactions is enhanced by the purchase of over-the-counter products by people who are not knowledgeable about herbs. Healthcare practitioners are responsible for finding better and safer ways to integrate medicine and must exercise sound judgment in this area. We encourage healthcare providers to expand their knowledge of herbs through education courses and thereby prevent unintended interactions.

Healthcare practitioners are responsible for finding better and safer ways to integrate medicine and must exercise sound judgment in this area. We encourage healthcare providers to expand their knowledge of herbs through education courses and thereby prevent unintended interactions.

AAPI (USA), May/June:34-35, (2004)