Investigation into the Effects of Tramadol, Citalopram, Tianeptine, and Their Combinations on Rat Brain Tissue

Background: Tramadol binds to opioid receptors and inhibits norepinephrine and serotonin reuptake, causing serotonin syndrome. Tianeptine stimulates serotonin reuptake and reduces serotonin levels. The aim of this study was to investigate whether tianeptine is effective against serotonin syndrome that may occur with serotoninergic drugs such as tramadol and citalopram. Methods: Rats were divided into eight groups (n = 6) that received tramadol (50 mg/kg), citalopram (10 mg/kg), or tianeptine (5 mg/kg) alone or a combination of tramadol + citalopram, tramadol + tianeptine, citalopram + tianeptine or tramadol + citalopram + tianeptine at the same doses administered to the stomach by oral gavage for 3 weeks. The healthy control group was given saline. Malondialdehyde, total glutathione, superoxide dismutase, and catalase levels were measured in removed brain tissues. The tissues were also examined histopathologically. Results: In the tramadol, tramadol + citalopram, and tramadol + citalopram + tianeptine groups, malondialdehyde levels were found to be higher compared to the control group, while glutathione, superoxide dismutase, and catalase levels were found to be lower. In other groups, values close to the control group were measured. Morphological degeneration was observed in neurons in the tramadol + citalopram group. The swelling of astrocytes and pericellular edema in oligodendrocytes were also observed. A significant population increase was noted in microglial cells. Blood vessels belonging to the tissue were observed to be severely dilated and congested. Histopathological damage was partially resolved in the group given tramadol + citalopram + tianeptine. Conclusions: The tramadol + citalopram combination caused severe oxidative stress in brain tissue. Tramadol alone caused mild damage in brain tissue, whereas tianeptine prevented the brain damage caused by tramadol. © 2025 by the authors.