Abstract

From a human safety perspective, the administration of ivermectin to food producing animal species entails potential risks related to the presence of drug residues in edible tissues, milk, and other derived products. The European Medicines Agency has established the maximum residue limits for ivermectin in the European Union, with values of 100 μg·kg-1 in fat and liver and 30 μg·kg-1 in kidney for all mammalian food producing species, in order to ensure that the amount of ivermectin that can be found in animal foodstuff is below dangerous levels for the consumers. According to these values, withdrawal periods after subcutaneous injection were recently established in the European Union (2009), in 49 days for products containing ivermectin as a single active substance or in combination with closantel, and in 66 days when combined with clorsulon. The marker residue for ivermectin was found to be H2B1a, which is the major component of the parent compound. The tissue distribution of residues and the overall ratios of marker to total residues were generally similar in most species, and the highest concentrations of ivermectin residues were found in fat and liver with high levels also detected in injection site muscles. Ivermectin is not licensed for use in animals from which milk is produced for human consumption, however its extra-label use should be considered regarding human safety, due to its long persistence in milk and milk-derived products.

Keywords: Edible tissues, ivermectin, maximum residue limits, milk, MRL, residues