Alternative Medicine and Chinese Herbs and the Kidney

Definitions

Complementary and alternative medicine (CAM) involves therapies that usually are not taught in Western medical schools. It includes a broad range of therapies and beliefs such as acupuncture, chiropractic care, relaxation techniques, massage therapy, and herbal remedies. According to the National Center for Complementary and Alternative Medicine (NCCAM) of the U.S. National Institutes of Health, complementary and alternative medicine is defined as a group of diverse medical and healthcare systems, practices, and products that presently are not considered to be part of conventional medicine. Although complementary medicine is usually used together with conventional medicine, whereas alternative medicine is used to replace conventional medicine, studies indicate that many patients who use alternative medicines also seek conventional treatment and vice versa. Therefore the terms “complementary” and “alternative” are used either together (complementary and alternative medicine, CAM) or interchangeably. Sometimes, the term integrative medicine is used to indicate the combination of mainstream medical therapies with CAM therapies that have some scientific evidence of safety and effectiveness.

Edzard Ernst commented in the Medical Journal of Australia that “about half the general population in developed countries use complementary and alternative medicine.” In the United Kingdom, the annual expenditure on alternative medicine is as high as $230 million. CAM therapies are classified by NCCAM into five categories ( Table 220.1 ). Traditional Chinese medicine includes acupuncture, acupressure, herbal medicine, tai chi, and qi-gong. The common characteristic of these diverse therapies is an emphasis on maximizing the body's inherent healing ability and on treating of the “whole” person by addressing his or her physical, mental, and spiritual attributes rather than focusing on a specific pathogenic process, as is emphasized in conventional medicine.

Herbs have been used for medicinal purposes for thousands of years in the developing world. The use of botanical medicine by far accounts for the majority of traditional remedies. Traditional medicine accounts for a substantial proportion of primary healthcare in Africa, Asia, and Latin America. In China, as much as 30% to 50% of the total medicinal consumption consists of traditional herbal preparations. Several single-center studies revealed that the consumption of traditional herbal preparations, especially Chinese traditional patent medicine, were still increasing in recent years in China.

Just as with conventional drugs, all herbal products are associated with adverse reactions. Indeed, the association of alternative therapies and kidney injury is well recognized. It is beyond the scope of this chapter to present an exhaustive list of possible side effects after intake of all the different types of herbs and plants. Instead, we will highlight certain important examples and discuss the possible therapeutic roles of traditional drugs in renal disease.

General Treatment Principles of Traditional Chinese Medicine

The concept of disease in Chinese medicine is different from that of conventional Western medicine. Disease is regarded as an imbalance between the health, qi, and pathogenic factors. This qi runs within the vessels and has a nutritive action. Sickness is also a result of yin-yang disharmony between different parts of the body ( zang-fu , internal organs) and in the whole body ( Fig. 220.1 , Table 220.2 ). Therefore the primary therapeutic principle of Chinese medicine is to strengthen the health qi , eliminate the pathogenic factors, and restore the yin-yang harmony of the body parts as well as with the environment. On the whole, Chinese medicine takes on a more holistic approach besides the use of herbs. Treatment targeting the kidney may not consist of treating illness arising from kidney dysfunction. Diarrhea can be stopped by herbs that “warm” the kidney with yang deficiency. Sexual impotence also can be treated by “warming” the kidney to revitalize yang . On the other hand, diuresis can be induced by warming the kidney with some other herbs in relieving edema caused by kidney yang deficiency.

Mechanisms of Nephrotoxicity of Herbal Medicine

The kidney is responsible for the excretion of chemicals and drugs. The high blood flow rate, large endothelial surface area, active uptake by tubular cells, and medullary concentration of toxins make the kidney vulnerable to the toxicity of drugs. A toxin may achieve a very high concentration in the renal tubules because of their concentrating capabilities. Herbal and plant products are among the most frequent causes of acute kidney injury (AKI) in Africa. Traditional herbal preparations are also important causes of AKI in China.

Herbal pharmacopoeias usually include active and useful compounds as well as toxic substances. The relative paucity of professional surveillance, the lack of industrial standardization, and the often-undisclosed secret formulas pose significant hazards to consumers. Furthermore, commercial plant products may lack purity or potency because of variability in the amount of ingredients. Herbal medicine may be the source of kidney injury via a number of mechanisms:

• 1.

  Known herb with unknown or underestimated toxicity

• 2.

  Toxic effect related to wrong preparation or use of substitute

• 3.

  Contaminants or adulteration

• 4.

  Indirect toxicity related to drug-drug interaction

They may result in a variety of clinical manifestations and/or pathologic changes in the kidney ( Table 220.3 ).

Herbs With Known Toxicity