Degenerative brain changes associated with tramadol use: an optical coherence tomography study

Tramadol—a synthetic opioid originally used as an analgesic—has been widely misused as an addictive drug in the middle east in the last twenty years. Brain changes associated with long-term tramadol use are understudied. This study aimed to detect the possible effects of tramadol use for at least one year on the brain. Optical coherence tomography (OCT) as a noninvasive measure can assess changes in retinal thickness which reflects degenerative changes in the brain. Twenty-five patients fulfilling the tramadol use disorder according to the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) criteria were compared to 25 matched control subjects free of substance use disorders. Other psychiatric and medical conditions that may affect OCT were excluded from both groups. Patients were assessed using Addiction Severity Index; meanwhile, both groups were evaluated using OCT. Patients with tramadol use showed a lower thickness of most OCT parameters than healthy non-tramadol controls. The retinal nerve fiber layer (RNFL) thickness was not associated with tramadol dose, duration of use, or the age of first use. There were differences between the right and left eyes in RNFL and Ganglion cell complex (GCC) thickness. Long-term tramadol use is associated with decreased thickness of RNFL that can be a potential marker and an early sign for degeneration detected by noninvasive techniques like OCT.