Carbamazepine is a pharmaceutical used in patients with seizures and bipolar disorder, which has been found in wastewater and many water resources. This is due to the inadequate disposal of pharmaceutical waste and the lack of treatment of municipal wastewater, as is the case in Colombia. The two main hydrographic basins of Colombia are the Cauca and Magdalena rivers, which are inhabited by the endemic species Striped Catfish (Pseudoplatystoma magdaleniatum). This has become an endangered species for various reasons, including the high contamination level of these rivers. In 2019, mature adult P. magdaleniatum of both sexes were caught in the Cauca river in Colombia. This was in order to assess the concentration of vitellogenin, as a biomarker of endocrine disruption, resulting from exposure to different levels of concentration of the emerging contaminant carbamazepine for 4 months. These tests were carried out in a fish farm. A significant decrease in the vitellogenin concentration was verified in females at concentrations of 25 µg l^-1 and 50 µg l^-1, and in males at 50 µg l^-1 of carbamazepine, with a significance level of p<0.05. Carbamazepine could cause a negative feedback in gonadotropin secretion, acting as an estrogen mimicker that causes a decrease in the level of vitellogenin.