The oxidative - antioxidative balance is the crucial mechanism of opioid-induced immunomodulation. Additionally, impairement of cognitive function during opioid therapy is another important side- effect. This phenomenon was clearly described in opioids abuse. This is interesting to evaluate the importance of this subjects in chronic pain patients. The aim of the study was to investigate the oxidative - antioxidative homeostasis and cognitive functions using serum total oxidative capacity (TOC) and total antioxidative capacity (TAC) tests and Brain Derivered Neutrophic Factor (BDNF) in patient with chronic non-cancer pain treated with opioids.

The project was approved in Ethical Committee and supported by Medical University of Bialystok (Poland). The serum TOC and TAC measurements were performed in total group of 50 adult patients: Study Group - 36 patients with chronic Low-Back Pain with opioids pharmacotherapy and Control Group - 14 patients, healthy volunteers. In Study Group anthropometric parameters, duration in opioid therapy, type of opioid, total dose, and form of application were registered.TOC, TAC, and BDNF measurements were performed using ImAnOx, PerOx, BDNF tests (Immundiagnostik, Germany).Data were analyzed using non-parametric tests.

Inclusion Criteria:

• minimally, 6 months opioid therapy in chronic Low- Back Pain

Exclusion Criteria:

• depression, steroids- local or systemic administration