Canadian Medical Association Journal 1996; 155: 216-219
© 1996 Kate Cottrell
The Canadian market for herbal medicines was valued at $150 million in 1995. "It's significant that there was about a 20% increase over 1994," says Leroy Fevang, executive director of the Canadian Pharmaceutical Association (CPhA). In keeping with growing public interest in alternative medicine, growth is expected to continue at an annual rate of about 15%.
Until a few years ago, the herbal-medicine market here was generally confined to Canadians of European, Asian or aboriginal heritage whose families and cultures had embraced herbal therapy for generations. Fevang says recent and unprecedented growth originated with "the more avant-garde consumers who challenge conventional medicine, but [interest] quickly spread to a much wider market."
The burgeoning interest has not gone unnoticed. McNeil Consumer Products recently launched Tanacet, a migraine prophylaxis medication made from the herb feverfew. McNeil's director of communications, Hélène Carty, attributes the appeal of herbal products to the current focus on wellness. Patients older than 50 are especially interested, she says, because conventional medications either have been ineffective, produced side effects or are contraindicated because of other medications the patient is taking.
The fact that more and more patients are likely to use some form of herbal medicine without their physician's knowledge is a concern. Dr. Anne Carter, associate director of the CMA's Department of Health Care and Promotion, fears that "the public is being misled into thinking that these things have effect" when there is little supporting evidence.
Like many physicians, Carter would like to see herbal medications subjected to outcome studies and quality-control standards, with evidence of risks and benefits being made available to consumers. Generally, such rules do not apply to most herbal therapies because they defy categorization: some are considered food supplements and a few fall into the drug category, but most hover in a no-man's-land between the two. Carter is concerned that such remedies are falling through the cracks left by Health Canada regulations.
The Health Protection Branch's (HPB) response to the issue is deceptively simple. If a manufacturer makes a therapeutic claim for a botanical product or wishes to market it in a quantity known (through the British Herbal Pharmacopoeia) to have a pharmacologic impact, it must be treated as a drug and subjected to the standard process of premarket authorization involved in obtaining a drug identification number (DIN). The manufacturer must produce evidence of efficacy, safety, stability and standardization. Packaging information must also have HPB approval.
Wendy Brown, marketing manager for Shoppers Drug Mart (SDM) corporate brands, looked into the process prior to the launch of SDM's Life Brand line of herbal medications in December 1994. Although the HPB relies on the British Herbal Pharmacopoeia to identify pharmacologically active herbs, Brown's proposal to provide documentation of efficacy from that and other respected European compendiums met with deafening silence. "They're used to seeing clinical trials, so that tells you what your chances of getting approval are," Brown says.
Dr. William LaValley, chair of the Medical Society of Nova Scotia's Complementary Medicine Section, shares that frustration. He feels it's unreasonable that the same restrictions on newly developed conventional pharmaceuticals should apply to "botanical products that have been in common usage without harm for centuries." LaValley suggests that "we need other categories that take existing usage and toxicity into account." Data are available, he says, although they may not always conform to the gold standard set by the randomized controlled trial. "[The opinion of] authorities in the field, such as master herbalists who know the benefits and the toxicities, should not be discounted."
Common wisdom suggests that drug companies can't justify the time and expense involved in getting a DIN because herbal products are not patentable, but some firms still may opt to go through the process. According to McNeil's Carty, Tanacet is the first herbal product to be subjected to the process; it needed a DIN because it exceeds an HPB-specified level of parthenolide, the active ingredient. Before launching the product, McNeil identified which species of feverfew had the highest level of parthenolide -- levels can vary dramatically between species -- and applied the same manufacturing and quality-control standards as for other medications. By providing clinical documentation of its efficacy as a migraine prophylaxis, McNeil gained the right to market Tanacet.
Carter believes this is good news: "I'd much rather see McNeil or some other major pharmaceutical manufacturers handling these products because I know they're using quality-control standards." A reliable manufacturer may in fact be a better indication of a consistent product than a DIN; Life Brand manufactures only mainstream herbal remedies for which there is a body of supporting literature, and products are tested to ensure standardization and shelf-life of the active ingredient. Brown is confident that product quality measures up to that of any product with a DIN.
But while there is little dispute over HPB's responsibility to ensure product quality, some feel that extreme conservatism regarding product packaging amounts to a dangerous suppression of information. "Why can't we have inserts that show the evidence and the reference material, and clearly give dosages?" LaValley asks. Even claims for vitamins, which have DIN numbers, are limited to a few vague statements, according to Brown. Both she and LaValley see a need to provide consumers with more information as well as appropriate disclaimers.
Although HPB regulations wield power in pharmacies, they carry comparatively little weight in businesses like health-food and bulk-food stores, where Fevang believes "sometimes the line between pure information and promotion becomes blurred." Many retailers have racks of pamphlets detailing the uses of botanical products, typically with little or no supporting evidence. Often they bear large-print but misleading advisories such as "For professional use only -- Not for public distribution."
Illegal products are available too. "For all that HPB works hard to regulate Canada," Brown comments, "there are products of this genre that are supposedly banned from sale in this country that you can get from under the counter at almost any Toronto health-food store." She says there is "a real problem between the rules and enforcement, and whether or not everything is in the right proportion."
Even though a few potentially dangerous products (such as melatonin) have been taken off the market, toxicity related to chronic use or overuse of alternative therapies still concerns some doctors. However, LaValley says that "the relative risk of toxic effect is dramatically lower with herbals than with conventional pharmaceuticals."
Pharmacists and physicians share concerns about people who self-medicate with herbs because of the small amount of accurate information that's readily available to the average consumer. Fevang says that "when it comes to clinical effectiveness, herbals are like any other medicine. The outcome you achieve depends on how closely you identify your problem and consider your medical history. People should discuss that [with a pharmacist or physician] to match their needs to the best product."
While researching herbal therapies for Shopper's Drug Mart, Wendy Brown found several that had specific contraindications -- but such information is suppressed along with the therapeutic claims. "All we can do is put the information in the hands of our pharmacists, and hope that the customers ask the right questions," she says. Brown also hopes that physicians will "make it their business to understand the benefits and limitations" of herbal remedies.
In recent years, the CPhA has been educating pharmacists about herbal products through a regular series in the Canadian Pharmaceutical Journal. Fevang says these articles might be compiled if there is enough demand "because physicians may have trouble accessing reliable information." LaValley believes there is an important need for continuing medical education in this area; until more physicians become well versed in medicinal herbs, LaValley advises doctors whose patients use them to "be open-minded, and either refer to someone who is expert or take the relatively small amount of time required to learn about the botanical extracts that can be used for your patient's condition."
The growing popularity of herbal medications appears to have taken the HPB, physicians, pharmacists and even drug companies by surprise. LaValley, who says explosive growth in the herbal-drug market is imminent, says large pharmaceutical companies are currently buying companies that produce herbal products. (A recent article in the Journal of the American Medical Association [see sidebar] noted that Boehringer, Boots and Ciba-Geigy have been purchasing these companies as investments.) In the long term, such purchases may enhance not only the credibility of the herbal-drug industry, but also the credibility of the products themselves.