Measurements in Swedish treated wastewater from a fairly large number of wastewater treatment plants indicate levels up to 6 ng/L, and in measurements in France up to 12 ng/L have been reported.
Toxicity studies are incomplete. Acute aquatic toxicity is low (LOEC 100 mg/L), which is the same as for glibenclamide.
Chronic studies as well as studies of mechanism-based effects in the environment are lacking for both substances.
Glibenclamide is included in the Stockholm County Council's table of pharmaceuticals with risk for negative environmental impact according to the environmental program 2017–2021, mainly based on the presence of glibenclamide in wild fish at concentrations close to therapeutic concentrations in humans. It is also reasonable based on the fact that glibenclamide has a high potential for bioaccumulation and concentrations found in Swedish wastewater. The risk of repaglinide accumulating in fish close to therapeutic concentration is significantly lower, although sales increase sharply.
The risk assessment can not be excluded, according to Fass.se, is due to toxicity studies being incomplete, why a risk calculation has not been possible. It is voluntary for manufacturers to provide information on the environmental impact.
Author: Department of Strategic Careers, Stockholm County Council.