Efficacy of mirtazapine in neuropathic pain model

Objective: Neuropathic pain, which is chronic pain, can affect the quality of life individuals. It can cause psychiatric problems such as depression and anxiety. Mirtazapine is an atypical antidepressant which has both noradrenergic and specific serotonergic receptor antagonism and shown to have anxiolytic, anti-emetic and appetite stimulating effects along with its antidepressant effect. It is generally tolerated better and has a different way of action when compared with other antidepressants used to treat neuropathic pain. Thus, we aimed to investigate its potential preventive effect in neuropathic pain in nerve ligated rat model. Methods: Forty rats were divided into five groups including the sham, the sciatic nerve ligation group and the third, fourth and fifth sciatic nerve ligation+mirtazepine groups which were treated with 5 mg, 10 mg and 15 mg/day mirtazapine, respectively. The tail flick and hot plate tests were performed on all the five groups, and the latency times were measured. Morphine was used as a positive control agent. Results: Administration of mirtazapine, restored both tail flick and hot plate latencies in a dose-dependent manner, meaning that mirtazapine is effective in treating neuropathic pain in this animal model. Mirtazapine also restored the antinociceptive response to morphine significantly. Discussion: Mirtazapine appears to be good candidate for both neuropathic pain treatment and accompanying psychiatric condition such as depression and anxiety with its dual effect on neurotransmitters.