PHARMACOVIGILANCE IN BRAZIL: THE MONITORING OF HERB-DRUG INTERACTIONS USING PHARMACOKINETIC DATA

Abstract

Consumption of herbal medicines has been increasing worldwide. In Brazil, the use of herbal medicines is expanding due to the misconception of the “innocuous nature” of this type of therapy. Herbal medicines, as like any other xenobiotic, may cause pharmacokinetic alterations in the organism, leading to changes in both phase 1 and phase 2 metabolism, due to enzyme inhibition or induction. In cases of the co-administration of herbal medicines with conventional drugs, the efficacy of the latter can be compromised, resulting in therapeutic failure. Because pharmacokinetic preclinical tests in herbal medicines are not a regulatory requirement, cases of herb-drug interactions (HDI) are mostly revealed in the post-market phase, i.e., by the pharmacovigilance system. Numerous countries have already reported cases of HDI through their respective pharmacovigilance systems to the World Health Organization (WHO), but Brazil did not have officially reported anyone so far. Moreover, during the first 10 years of monitoring, no HDI have been clearly established for Brazilian herbal medicines. It is known that, approximately, 90% of the Brazilian population use herbal medicines and, therefore, cases of HDI might be occurring without being noticed or formally reported. This could be changed by the adoption of several strategies, such as the continued education of health professionals, the encouragement of these professionals to report cases of HDI to the pharmacovigilance systems, the inclusion of traditional practitioners to the public health system and campaigns to prevent the self-medication of herbal medicines by the general public.