Carbamazepine effects on pain management and serum IL-6, IL-10 evaluation in addicted patients undergoing surgery.

Postoperative pain control remains an important issue in the field of surgery. Assessing and managing patients with acute pain who are addicted to opioids are often challenging. It has been shown that, addicted patients are less tolerant to pain. There is limited evidence to guide the management of acute pain in these patients. Here we studied the effect of preemptive use of carbamazepine on pain behavior and serum IL-6, IL-10 levels in the addicted patients. 90 male patients (25-45 years, BMI 20-27), were divided into 3 group of 30 patients: 1- control, 2- addicted, 3- addicted patients receiving carbamazepine 400mg before surgery. The visual analog pain scale and serum levels of IL-6 and IL-10 were evaluated at time 0 (before surgery), 1 and 12h postoperatively. Compared with control and carbamazepine groups, addicted patients exhibited exaggerated pain behavior before and after surgery, however, postoperatively, a significant increase in pain behavior was seen in control compared to carbamazepine group. A decrease in serum IL-10 and an increase in IL-6 concentrations were observed in addicted patients. In the morphine abuser, a decrease in pain threshold, an increase in IL-6 and a decrease in IL-10 levels were evident compared with non-abuser subjects. Addition of carbamazepine improved pain sensation and serum IL-6 levels and a reduction in serum IL-10 level in control patients was paralleled to their recovery. It seems that, preemptive use of low dose of carbamazepine can improve postoperative pain and cytokine activities in the addicted patients.

Minocycline Effects on IL-6 Concentration in Macrophage and Microglial Cells in a Rat Model of Neuropathic Pain.

BACKGROUND: Evidence indicates that neuropathic pain pathogenesis is not confined to changes in the activity of neuronal systems but involves interactions between neurons, inflammatory immune and immune-like glial cells. Substances released from immune cells during inflammation play an important role in development and maintenance of neuropathic pain. It has been found that minocycline suppresses the development of neuropathic pain. Here, we evaluated the analgesic effect of minocycline in a chronic constriction injury (CCI) model of neuropathic pain in rat and assessed IL-6 concentration from cultured macrophage and microglia cells. METHODS: Male Wistar rat (n=6, 150-200 g) were divided into three different groups: 1) CCI+vehicle, 2) sham+vehicle, and 3) CCI+drug. Minocycline (10, 20, and 40 mg/kg) was injected one hour before surgery and continued daily to day 14 post ligation. Von Frey filaments and acetone, as pain behavioral tests, were used for mechanical allodynia and cold allodynia, respectively. Experiments were performed on day 0 (before surgery) and days 1, 3, 5, 7, 10, and 14 post -injury. At day 14, rats were killed and monocyte-derived macrophage from right ventricle and microglia from lumbar part of the spinal cord were isolated and cultured in RPMI and Leibovitz's media, respectively. IL-6 concentration was evaluated in cell culture supernatant after 24 h. RESULTS: Minocycline (10, 20, and 40 mg/kg) attenuated pain behavior, and a decrease in IL-6 concentration was observed in immune cells compared to CCI vehicle-treated animals. CONCLUSION: Minocycline reduced pain behavior and decreased IL-6 concentration in macrophage and microglial cells.

The Attenuation of Pain Behavior and Serum COX-2 Concentration by Curcumin in a Rat Model of Neuropathic Pain.

BACKGROUND: Neuropathic pain is generally defined as a chronic pain state resulting from peripheral and/or central nerve injury. There is a lack of effective treatment for neuropathic pain, which may possibly be related to poor understanding of pathological mechanisms at the molecular level. Curcumin, a therapeutic herbal extract, has shown to be effectively capable of reducing chronic pain induced by peripheral administration of inflammatory agents such as formalin. In this study, we aimed to show the effect of curcumin on pain behavior and serum COX-2 level in a Chronic Constriction Injury (CCI) model of neuropathic pain. METHODS: Wistar male rats (150-200 g, n = 8) were divided into three groups: CCI vehicle-treated, sham-operated, and CCI drug-treated group. Curcumin (12.5, 25, 50 mg/kg, IP) was injected 24 h before surgery and continued daily for 7 days post-surgery. Behavioral tests were performed once before and following the days 1, 3, 5, 7 after surgery. The serum COX-2 level was measured on day 7 after the surgery. RESULTS: Curcumin (50 mg/kg) decreased mechanical and cold allodynia (P < 0.001) and produced a decline in serum COX-2 level (P < 0.001). CONCLUSIONS: A considerable decline in pain behavior and serum COX-2 levels was seen in rat following administration of curcumin in CCI model of neuropathic pain. High concentration of Curcumin was able to reduce the chronic neuropathic pain induced by CCI model and the serum level of COX-2.