Role of anticonvulsants for the treatment of chronic pain
Anticonvulsants are commonly used and have been widely accepted for the management of various types of chronic pain, including neuropathic pain, migraine, and other headache disorders and fibromyalgia, for example. As a class, these agents with various mechanisms of action are believed to result in their analgesic effect by reducing ectopic neuronal discharges. As these agents are described further in specific syndromes in other chapters, only general comments will be covered in this chapter. Phenytoin and carbamazepine were the first anticonvulsants to have demonstrated analgesic efficacy on the basis of controlled clinical trials. Although many of the trials have been conducted as monotherapy versus placebo, several recent trials have explored the role of certain AEDS in combination with other pharmacologic agents (opioid or non-opioid). The prescriber should consider not only the mechanism of action, potential for drug-drug interactions, and adverse effect profile of the AED being considered, but also the evidence for its use in a specific chronic pain condition prior to prescribing.