Coadministration of tramadol with aripiprazole and venlafaxine—The effect on spatial memory functions in male rats

BackgroundThe impairment of memory functions is very common in patients with chronic pain, particularly in patients with existing cognitive disorders. Results of some studies confirmed that tramadol (TRM), a frequently prescribed analgesic drug, improves memory functions in humans. However, there are no studies on the effect of co-administration of TRM with antidepressants or antipsychotics on memory; therefore, the aim of this study was to evaluate the effect of concomitant use of TRM with a second generation antipsychotic–aripiprazole (ARI) and an antidepressant–venlafaxine (VEN) on memory using an animal model.MethodsThe effect of TRM (5 mg/kg) + ARI (1.5 mg/kg) and TRM (5 mg/kg) + VEN (20 mg/kg) on memory in Wistar rats was examined using the Morris water maze test after single and chronic administration (7 and 14 days).ResultsIt was observed that a single and chronic administration of TRM, VEN or ARI alone, but not a combination of TRM + VEN or TRM + ARI (except for 14 days of treatment) can improve memory in rats compared to the control group. After 14 days of administration, both combinations achieved improvement similar to each drug individually and improved spatial memory in rats compared to the control animals.ConclusionIt can be assumed that chronic treatment with combinations of TRM + VEN or TRM + ARI is unlikely to cause memory impairment and interfere with either any antidepressant effect of VEN or any antipsychotic effect of ARI in patients suffering from chronic pain using TRM.