[Pharmacological treatment of neuropathic pain]

Abstract

Neuropathic pain, i.e., pain resulting from functional changes in peripheral and central pathways subsequent to injury to the peripheral nervous system, offers a most difficult challenge to therapy. To date, only the antidepressants and the anticonvulsants have shown any effectiveness, albeit incomplete and inconsistent, and many questions remain unanswered: What are the exact indications for the antidepressants? What component of neuropathic pain do they relieve, and through which mechanisms? Which type of antidepressants should be prescribed? A first-generation tricyclic? Or a new compound with a selective action on serotonin reuptake? What are the effective dosage and duration of the treatment? What is it mechanism of action? What other antalgic effects do carbamazepine and baclofen possess apart from their action on trigeminal neuralgia? The opiates are generally considered to be without effect, but recent clinical and experimental findings seem to point otherwise. In the meantime, following a few simple rules will optimize the benefit of drug treatment in neuropathic pain: treatment tailored to individual cases; adequate dosage and duration of treatment. However, it is from the near future that breakthroughs are being expected, dues to the multiplication of animal models and more accurate analysis; new clinical evaluation tools which help in distinguishing the different mechanisms underlying the various aspects of pain; the development of new substances, such as capsaicin, local anesthetics, anti-inflammatory agents (NSAIDs for example); and better defined methodological conditions for therapeutic trials.