Pharmacovigilance of Herbal Drugs (Herbovigilance)

Abstract

Improved traditional medicine/phytomedicine formulations have gained a global acceptability and popularity as therapeutic agents for many diseases in Sub-Saharan Africa. Herbal products are generally considered as safe, environmentally friendly and increasingly consumed by the community without a prescription. There is a lack of systematic data on traditional medicine- associated adverse effects due to complex issues such as products with multiple ingredients, poor standardization, lack of clinical trials, variation in manufacturing processes, contamination, adulteration and misidentification of herbs. The aim of pharmacovigilance is to detect, assess, understand, and prevent the adverse effects or any other possible drug-related problems, related to herbal, traditional and complementary medicines. Pharmacovigilance for herbal medicines is in its infancy, and monitoring the safety of natural products presents unique challenges, and as such, preparations are available from a wide range of sources where limited qualified healthcare professionals are available. The ethico-legal issues and regulatory approval mechanism of herbal medicine vary from country to country. This paper also elucidates the level of challenges associated with herbal pharmacovigilance geared towards improving safety monitoring for herbal medicines in the future. The importance of herbal remedies in pharmacovigilance systems is becoming one of the primary tasks, due to the constantly ascending potential of herbal products and herbal medicines worldwide. Nowadays, the drug development is focused on finding new active compounds or combinations, but costs are simultaneously growing, which makes herbal medicines an attractive, harmless and cheaper alternative to synthetic drugs.
Like all drugs, herbal are not free of risk and many studies suggest for potential adverse reactions and interactions. Available statistics show that some herbal products, used in traditional medication for generations, may possess carcinogenic, hepatotoxic, cardiotoxic and other severe actions. Evaluation of the safety should include at least in vitro and in vivo genotoxicity assays, long-term rodent carcinogenicity tests (for drugs intended to be continuously used for >3 months or intermittently for >6 months), reproductive and developmental toxicity studies in some cases and examination of the effects on drug-metabolizing enzymes.
Drug safety of herbal medicines should be developed, focusing on specific groups of patients. Herbal formulations being widely accepted therapeutic agents as antidiabetics, antiarthritics, hepatoprotectives, cough remedies, memory enhancers, and adaptogens. The commonest myth regarding herbal medicines is that these medicines are completely safe, and can therefore be safely consumed by the patient on his/her own, without a physician's prescription. This belief has led to large-scale self-medication by people all over the world, often leading to disappointing end-results, side-effects, or unwanted after-effects. There is an increasing awareness at several levels of the need.