Comparison of morphine and tramadol effects on phagocytic activity of mice peritoneal phagocytes in vivo

It has been claimed that, in contrast to most opioids, tramadol does not suppress immune functions. We therefore, studied the effects of tramadol in comparison to morphine, on the number of phagocytes and the number of sheep red blood cells (SRBCs) engulfed by each individual cell (phagocytic index) of mouse peritoneal phagocyte. In an experimental study, 63 BALB/c mice received morphine, tramadol or saline intraperitoneally. On days 3, 5, and 10, the peritoneal phagocytes were incubated with an equal number of SRBCs. The cells were then cytocentrifuged onto gelatin-coated slides and examined microscopically. Ten days after the start of drug administration, the number of phagocytes and the phagocytic index reduced in morphine group (P < 0.05), and enhanced in tramadol group (P < 0.05). In conclusion, tramadol stimulation of immune system may offer a good alternative to morphine for the treatment of patients in whom immunosuppression might be hazardous or in patients who cannot tolerate the side effects of morphine.