Trends in researching and reporting on herbal-drug interactions

There is a lack of basic knowledge about the affirmation that herbs, vitamins, and other dietary supplements may augment or antagonize the actions of prescription and nonprescription drugs. This event should be taking account as to the indications for use and safety of herbal medicines regarding the possibility of herbal-drug interactions. The objectives of this study were to review the literature for evidence and tendencies on the use, safety and pharmacology of herbal-drug interactions. To do it was searched the PubMed electronic database papers regarding to "herbal-drug interactions" until December 2007 and compiled data according to the grade of evidence found. It was compiled a total of 413 papers related with the approached topic. The drugs more studied were warfarin, anti-neoplastic agents and digoxin and the herbals were hypericum, ginkgo, panax, kava, garlic, valerian and tea. The major investigations were executed on in vitro studies, principally on cytochrome P450 and P-glycoprotein. On the in vivo pre-clinical investigation; it was researched that the major papers used rats, mice, rabbits, and others. The countries with more publications were USA, Canada, United Kingdom, Japan, Germany, Australia, and Italy; the principal authors and Institutions were also from these countries. There was an increase in the published articles from 1999 reaching the maximal production in 2006 (74 papers). The journal with the major number of papers was Br J Clin Pharmacol. The type of article more written was the Review and the English was the language more used in these papers. There is an obvious interest regarding the herbal-drug interactions manifested in the increasing of the number of paper published about this topic. These investigations are not sufficient if we taking account the herbal medicine is one of most popular choices of complementary therapies and it could induce interactions with the conventional medicines translated in a deficient treatment or adverse reactions that conduce to an erroneous therapy. It is important to recognize that there are not papers from Latin-American & Caribbean region related with herbal-drug interactions.