Effect of morphine versus tramadol on the immune response during the management of patients with chronic cancer pain

Abstract EN

Background Although the inter-relationship between opioid analgesics and the immune system is not a simple one and may appear to vary depending on the opioid studied, the dose range of the opioid, the species in which studied, the immunological parameters measured, and the time course of the study, increasing availability of data indicates that opioid prescription and usage is lagging behind the available evidence of significant opioid-induced immunosuppression in humans in a variety of disparate situations.

Methods Seventy patients complaining of cancer-related pain were randomly assigned to two groups of 35 patients each.

The tramadol group was treated with tramadol hydrochloride 100–200 mg three times daily and followed up.

The morphine group was treated with controlled-release morphine sulfate tablets 30–60mg twice daily and followed up.

Systolic and diastolic arterial blood pressure, the mean heart rate, and the mean respiratory rate were measured.

Pain was assessed by verbal rating score and the psychological state of the patients was assessed using the General Practitioner Assessment of Cognition score.

The daily activities of the patients were assessed by the Lawton Instrumental Activities of Daily Living Scale and were reported before starting therapy, 2, 4, and 6 weeks later.

A laboratory study was performed by measuring the serum level of interleukin (IL)-2, and interferon (IFN)-g before treatment, and after 2 weeks and 6 weeks.

Results There was a significant difference in the respiratory rate, verbal rating score, and psychological state of the patients between the two groups.

The concentration of IL-2 in the serum of patients in the morphine group decreased significantly compared with that in the pretreatment phase (174.86 ±31.91, 124.44 ± 33.68, and 110.2± 22.46 pg/ml), respectively, whereas it increased in the tramadol group compared with the pretreatment phase (177.14 ±20.83, 217.87 ± 24.01, and 219.58± 21.03 pg/ml); these changes were statistically significant.

The concentration of IFN-g in the serum of patients in the morphine group was found to decrease significantly compared with that in the pretreatment phase (106.82± 4.52, 97.62 ± 10.17, and 95.89 ±9.59 pg/ml), respectively, whereas it increased significantly in the tramadol group than that in the pretreatment phase (101.72 ±2.99 pg/ml, 125.51 ±8.71 pg/ml, and 139.93 ±6.35 pg/ml), respectively.

Both IL-2 and IFN-g showed no significant changes between both groups at baseline value, while later on, they were significantly higher in tramadol group than morphine group at all other studied periods.

Conclusion There were significant changes in the immune response and adequate pain relief in cancer patients treated with either tramadol or morphine, with fewer side effects than expected.