Herbal Medicine use in the Australian Population: Adulteration, Contamination and Adverse Drug Reactions

Abstract

Herbal medicines are perceived to be safe by consumers and health practitioners alike, despite growing evidence of wide spread adulteration and contamination. The substandard quality of herbal medicines, coupled with their escalation in popularity, coincide with an increase in adverse drug reactions (ADRs) to herbal medicines. With little known about the quality of herbal medicines used in Australia, it is possible that ADRs are not only in response to the active ingredient, but possibly caused by adulterants, contaminants, and a lack of awareness regarding herb-drug interactions. Herbal medicines have been used in traditional medicinal practice across many cultures and centuries. However, the modern medicine market place has changed, and the herbal medicine industry has had to adapt. Chapter one titled “Traditional Medicine, Modern Issues” explores the evolution of Western Herbal Medicine and its associated risks. The role of herbal medicine in the treatment of common psychiatric disorders has become more established over the past decade, yet the quality of such preparations is not fully understood. Chapter two titled “Adulterants and Contaminants in Psychotropic Herbal Medicines Detected with High Performance Liquid Chromatography and Next Generation DNA Sequencing” found adulteration and contamination of 96% of tested psychotropic herbal medicines. This shows that these preparations are a potential health risk. A large proportion of Australian pain sufferers are seeking herbal medicines to treat their condition. Chapter three titled “Combined Liquid Chromatography-mass spectrometry and Next Generation DNA Sequencing Detection of Adulterants and Contaminants in Analgesic and Anti-inflammatory Herbal Medicines” investigated the purity of 49 anti-inflammatory and analgesic herbal medicines and as for psychotropic herbal medicines found high levels of adulteration and contamination. To assess the extent of adulteration and contamination of herbal medicines internationally, Chapter four titled “An analysis of Vietnamese Traditional Herbal Medicines for prescription and non-prescription drugs, herbicides and pesticides” analysed a selection of Vietnamese herbal medicines. The results showed no evidence of augmentation with synthetic pharmaceuticals, herbicides or pesticides, demonstrating that the adulteration and contamination of herbal medicines is not universal. ADR reports have long been used as a surveillance tool to detect adverse reactions to drugs within a population. The overall impact of herbal medicines on the Australian population is currently unknown, largely due to the tendency for herbal ADRs to be underreported. Chapter five titled “Analysis of spontaneous adverse drug reactions to Echinacea, Valerian, Black Cohosh and Ginkgo in Australia during the period 2000-2015” analysed ADRs to commonly used herbal medicines. The results showed the most severe ADRs involved herb-drug co-administration, emphasising the risk that herb-drug interactions can pose. To compare ADRs to herbal medicines with ADRs to equivalent synthetic medicines, Chapter six titled “A comparison of patterns of spontaneous adverse drug reaction reporting with St. John's Wort and fluoxetine during the period 2000-2013” compared ADRs to a herbal selective serotonin reuptake inhibitor (SSRI) with ADRs to a synthetic SSRI. Results showed they had a similar profile of severity. The accuracy of labelling on herbal medicine products and clear health warnings is an important health, legal and environmental issue. Chapter seven titled “Hypersensitivity Adverse Drug Reactions to Glucosamine and Chondroitin Preparations in Australia Between 2000 – 2011” highlights this importance, with particular respect to allergic-type reactions. In Australia, the common belief is that herbal medicines are rigorously monitored for safety and efficacy by regulatory bodies, when in fact, the regulation of the herbal medicine industry is largely self-assessed and trust-based. The work presented describes the state of herbal medicine in Australia to show widespread adulteration and contamination, and improves public understanding of the risks associated with herbal medicine use, particularly in conjunction with prescribed medicines.