Ayurvedic drugs pose severe health risk

drug_at_watchdo.com
Date: 10/08/04 

Date: 08 Oct 2004 21:27:44 GMT

   Toxic Heavy Metals and Undeclared Drugs in Asian Herbal Medicines
   by Edzard Ernst
   This article will also appear in Trends in Pharmacological Sciences.
   Issue 120
   Abstract Asian herbal medicines are currently used by large sections
   of the population. Because they are not regulated as medicines and are
   freely available to everyone, serious safety concerns might be
   associated with these herbal medicines.
   In this article, evidence suggesting that some Asian herbal medicines
   contain toxic heavy metals or undeclared prescription drugs is
   reviewed. In particular, Indian and Chinese preparations have been
   implicated.
   Although adulteration with drugs is by definition fraudulent, the
   inclusion of heavy metals could be either intentional for alleged
   medicinal purposes or accidental.
   Evidence from various countries implies that toxic heavy metals and
   undeclared prescription drugs in Asian herbal medicines might
   constitute a serious health problem. However, the majority of the data
   is anecdotal and insufficient to define prevalence figures.
   Ways ought to be found to maximize consumer safety.
   In most developed countries, Asian herbal medicines (AHMs) are
   becoming more and more popular [1]. However, usually AHMs are not
   regulated as medicines. Problems might arise as a result of the lack
   of adequate regulations, the pharmacological complexity of herbal
   products, and the paucity of information on the pharmacology and
   toxicity of these compounds. AHMs can be purchased from outlets
   ranging from health-food stores to Internet sites, and thus a crucial
   evaluation of their safety is relevant and important.
   One obvious safety issue relates to the possibility that some AHMs
   contain heavy metals or undeclared drugs [2]. Based on a review of the
   recent medical literature (Medline, Embase 1990-2001), this article
   aims to summarize the recent evidence pertaining to this subject.
   Indian Remedies Indian medical systems (e.g. Ayurveda and Unani) have
   a long and rich history of herbal medicine, and heavy metals have been
   a regular and deliberate constituent of traditional Indian remedies
   [3]. Thus, to use the term "contamination" with respect to the
   presence of heavy metals in such remedies might be misleading (see
   below).
   A London-based toxicology unit published a case series of adverse
   events associated with traditional medicines that were reported to
   them between 1991 and 1995 [4]. Of 12 cases of poisoning with lead,
   arsenic or mercury, nine cases were associated with herbal remedies
   from India and the remainder was due to traditional Indian cosmetics
   (e.g., "surma.")
   A recent exemplary case report from Italy [5] (box 1) exhibits many
   hallmarks of such cases: desperate parents, non-medically qualified
   healers, lack of product standards, undeclared ingredients,
   nondisclosure of usage and long-term medication, in addition to delay
   of diagnosis of poisoning and hence delay of effective therapy. Indian
   authors recently analyzed 31 Ayurvedic formulations obtained in India
   for their mercury content [6].
   With the exception of one remedy, all exceeded the legal limits of 1
   ppm mercury and 16 preparations exceeded the limits by more than two
   orders of magnitude. These authors also noted that huge variability of
   mercury content existed within one allegedly identical remedy
   manufactured by different companies.
   No recent systematic investigations are available about the prevalence
   of heavy metal content of traditional Indian remedies on sale in
   developed countries.
   Thus, a considerable degree of uncertainty continues to surround this
   area.
   Chinese Remedies Numerous case reports and case series of heavy metal
   poisoning associated with the use of traditional Chinese medicines
   (TCMs) have been published [7]; lead has relatively often been
   implicated as the cause of such poisoning but mercury, cadmium,
   arsenic, copper, and thallium have also been found in TCMs [7].
   Californian officials have screened for undeclared pharmaceuticals and
   heavy metals in imported Chinese remedies on sale in Californian
   herbal retail stores [8]. Seven percent of the 251 products tested
   contained undeclared pharmaceuticals (e.g., ephedrine,
   chlorpheniramine, methyltestosterone, and phenacetin). Twenty-four
   products contained at least 10 ppm lead, 36 contained an average of
   14.6 ppm arsenic, 35 contained an average of 1,046 ppm mercury, and 23
   had more than one contaminant and/or adulterant.
   Koh and Woo [9] reported the detection of toxic heavy metals that
   exceeded Singapore's legal limits in 42 Chinese proprietary medicines.
   They collected 2,080 samples of such medicines in Singapore and tested
   them for heavy metal content. Forty-two different medicines were found
   to contain metals in amounts exceeding the legal limits.
   Mercury was found in 28 products, lead in eight, arsenic in six, and
   copper in one. One product contained both mercury and lead and another
   product contained both mercury and arsenic. Melchart et al. [10]
   analyzed all 317 batches of dried Chinese herbs delivered to a German
   hospital of Chinese medicine.
   Heavy metal content beyond the legal limits was detected in 3.5% of
   these samples. Obviously, heavy metals are not the only possible toxic
   ingredients in herbal remedies; contamination with herbicides,
   pesticides, microorganisms; or mycotoxins, insects, or undeclared
   herbal constituents are other relevant possibilities [2,11-13].
   Moreover, contamination with toxic herbal constituents (e.g., through
   misidentification of the herbal ingredients) can be a serious problem.
   In Belgium, the use of a TCM contaminated with plants from the
   Aristolochia species resulted in an epidemic of subacute intestinal
   nephropathy. Many of the affected patients required kidney
   transplantation. When 19 kidneys and urethras removed from ten such
   patients were examined histologically, there were conclusive signs of
   neoplasms in 40% of cases [14].
   Numerous case reports originating from countries such as Australia,
   Belgium, China, the Netherlands, New Zealand, United Kingdom, and
   United States demonstrate the adulteration of TCMs with synthetic
   drugs and associate the use of adultered remedies with health problems
   of the user [15]. The adulterants include a wide range of
   pharmaceuticals (box 2). The resulting clinical consequences are often
   serious and sometimes life threatening: agranulocytosis, Cushing's
   syndrome, coma, the excessive increase of the international normalized
   ratio (INR) have all been reported.
   In other cases, the adulterants caused no symptoms at all and the
   problem was discovered only through routine check-ups or through the
   remarkably good clinical response, which turned out to be due not to
   the TCM but to the undeclared prescription drug.
   Analyses are available of Chinese herbal medicines collected in
   Australia [16], Taiwan [17] and UK [18]. The largest of these studies
   is that of Huang and colleagues from Taiwan [17], who showed that 24%
   of all 2,609 samples collected contained at least one adulterant.
   This high prevalence was due to the fact that the samples were
   associated with reports of adverse effects and poisoning, and possibly
   included low-grade folk remedies. Examples of recent case reports
   [19,20] are illustrated in boxes 3 and 4.
   Concerns About the Safety of Asian Herbal Medicines
   These data raise concerns about the safety of consumers using AHMs.
   Both toxic heavy metal content and adulteration with prescription
   drugs have been reported. To date, few data are available to calculate
   the prevalence of these problems reliably in developed countries.
   A recent press release [21] of the British "Medicines Control Agency"
   stated that this regulatory body "continues to find potentially
   dangerous and illegal ingredients in TCMs. Recently TCMs have been
   found to include . . . mercury and arsenic . . . [and] prescription
   only steroids." It is notable that the majority of clinical problems
   occur with self-prescription of AHMs.
   One could therefore argue that consulting an experienced herbal
   practitioner might avert adverse events; however, evidence is required
   to support this claim. Several possibilities exist to explain the
   presence of heavy metals in AHMs. First, heavy metals could be
   included intentionally for alleged medicinal properties.
   Some Indian schools of medicine emphasize the importance of metals
   such as lead, copper, gold, iron, mercury, silver, tin and zinc for
   the proper function of the human body [22]. Ayurvedic textbooks, for
   example, take note of the toxicity of heavy metals and recommend
   special physicochemical processes that, according to ancient Indian
   belief, "detoxify" such toxic heavy metals (e.g. by heating them until
   they glow [23]).
   In traditional Chinese medicine, mercury is part of some preparations
   under the terminology of "cinnabaris" (mercury sulfide), "calomel"
   (mercury chloride) or "hydrargyri oxydum rubrum" (mercury oxide). Such
   products are used for a variety of indications including, for example,
   as a tranquilliser, an anti-epileptic, for ulcers or to treat insomnia
   [9]. Lead is used as "Mi Tuo Seng" (Lithargyrum) [24] and arsenic as
   "Xiong Huang" (Realgar) [25] in the manufacture of several TCMs.
   Strictly speaking, these constituents are thus not contaminants but
   ingredients deliberately included for a specific curative purpose.
   Second, the presence of heavy metals might be the result of
   contamination during manufacture, for example, from grinding weights
   or lead-increasing containers or other manufacturing utensils [9].
   Third, AHMs might contain heavy metals when grown on seriously
   polluted soil [26].
   In this context it is relevant to note that TCMs might also contain
   animal and mineral products and that these too might be contaminated
   with heavy metals [27].
   Although contamination can be accidental, adulteration is, by
   definition, fraudulent. The reasons why some AHMs contain prescription
   drugs are speculative. I suspect that some manufacturers include such
   ingredients to render their products more clinically effective. If
   this is the case, it seems obvious that the inclusion of prescription
   drugs is fraudulent and illegal.
   Many consumers are motivated to try AHMs through a misconception that
   these remedies are inherently safe [28], and there is evidence that
   the (UK) daily press have their share in perpetuating this myth [29].
   Approximately half of the individuals using herbal medicines do not
   tell their physician [30]. This level of non-communication further
   increases the risk to the consumer because doctors might fail to
   diagnose adverse effects caused by treatments of which they are not
   aware. The majority of people taking herbal remedies combine them with
   conventional drugs [30]. This opens the possibility of herb-drug
   interactions [31,32], which, in turn, further raises concern about
   consumer safety.
   Recent evidence suggests that consumers are beginning to become
   concerned about the risks of under-regulation of dietary supplements,
   and the majority of US consumers now seem to support [33]: (1) the
   requirement that the Food and Drug Administration (FDA) review the
   safety of new dietary supplements before their sale; (2) increased
   authority to remove from sale those products shown to be unsafe; and
   (3) increased government regulation to ensure that advertising claims
   about the health benefits of dietary supplements are true.
   How can the risk to patients be minimized? An appropriate strategy
   [34,35] (box 5) should follow several avenues. The consumer should be
   informed that "natural" does not necessarily mean 'free from risk' and
   that adverse effects as a result of AHMs are an undeniable reality.
   Patients and physicians should be encouraged to talk about the use of
   AHMs and other complementary/alternative treatments [34] and the
   possibility of interactions of herbal medicines with prescribed drugs
   [31,32].
   Regulators should consider measures to control this sector of
   healthcare more effectively. It is concluded that toxic herbal metals
   and undeclared drugs in AHM represent a potentially serious problem
   that puts consumers at risk. Means of minimizing this risk must be
   found and implemented.
   Wang, Ang, b. 1615; Hu, Tsung-wen Shen-nung pen ts'ao pei yao i fang
   ho pien (Herbal and Prescriptions) China, 1740. 6 vols. from The
   National Library of Medicine.
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