Metformin and guanylurea reduce survival, but have limited sublethal effects in larval zebrafish (Danio rerio)

Abstract Metformin is the most common first-line oral therapeutic agent used in the treatment of type-2 diabetes, one of the most prevalent chronic diseases in North America. Post excretion, the compound enters wastewater treatment plants where it is partially bio-transformed by bacteria into guanylurea. Both metformin and guanylurea enter freshwater environments in wastewater effluent where they are available for uptake by aquatic biota. …