Objectives: The treatment of neuropathic pain is mainly based on antiepileptics, tricyclic antidepressants, and opiates. These drugs have important side effects disturbing the patient's quality of life. Mirtazapine (MTZ) is a new and well-tolerated tricyclic antidepressants with both monoaminergic and opioid properties that might favorably influence pain. The aim of this study was to assess whether MTZ can reduce the pain induced by a standardized stimulus presented to healthy human participants. The nociceptive flexion reflex (NFR) to an electric stimulus was chosen to determine the pain threshold.
Methods: The effect of MTZ compared to placebo was assessed on 10 healthy participants in a double-blinded cross-over design. The NFR was measured the day after a single oral dose of drug (30 mg) or placebo.
Results: A significant increase in upper limb (+29%, P=0.006) NFR threshold was observed.
Discussion: MTZ increases the pain tolerance in healthy participants. The potential benefit of this effect on pain should be investigated more thoroughly in chronic neuropathic pain patients. The NFR might serve as an additional tool for the monitoring of these patients.