Effects of anti-diabetic pharmaceuticals to non-target species in freshwater ecosystems: A review

Abstract

Diabetes Type 2 is among the most common metabolic disorders that human beings face. As the number of diabetic patients increases, the demand for production of antidiabetic drugs also increases. This, in turn, raises environmental concerns since these drugs eventually reach water bodies through various means like, excretory wastes by the patients. It is urgent to make the appropriate legislation to control and regulate the flow of hypoglycemic pharmaceuticals such as metformin into natural lakes and drinking water reservoirs before undesirable and irreversible changes occur in these waterbodies. The use of metformin leads to the environmental release of this drug into the waterbodies. Mexico is one of the nations with the highest number of obese patients and the quantity of metformin administered per patient can be up 2500 mg/day. There are also other products such as alphaglucosidase inhibitors thiazolidinediones, and meglitinides that have the potential to reach aquatic ecosystems. Information related to their concentrations in natural waters, their metabolites or effects on nontarget organisms is scarce. Most studies on the effects of metformin on aquatic organisms have been on fish, algae, and bacteria while zooplankton have received much less attention. This is surprising since zooplankton species are the principal link between phytoplankton and fish larvae and are more sensitive to stress than algae. Flocculation, activated carbon filtration, ozonisation, and chlorination are ineffective in removing metformin and guanylurea. Therefore, other means of waste disposal of unused antidiabetic drugs must be pursued than treating wastewaters containing them. Metformin and guanylurea are highly water soluble and the available information on the adverse effects of antidiabetic drugs is scarce and restricted to a few groups of aquatic organisms. It is therefore urgently needed to generate appropriate legislation to control and regulate the flow of orally administered pharmaceuticals such as metformin into natural lakes and drinking water reservoirs before undesirable and rreversible changes occur in these waterbodies.