Adjuvant analgesics in neuropathic pain.

Conventional analgesics have limited efficacy in the management of neuropathic pain. An adjuvant analgesic is a drug that has a primary nonpain indication but which may be analgesic in certain circumstances, and many of these have established a role in the pharmacological treatment of neuropathic pain. The number needed to treat is an indirect statistical measure that can be used to compare relative efficacy of different adjuvant analgesics and, from this, there is currently insufficient evidence to suggest that any one adjuvant analgesic has absolute advantages over another. Analgesic efficacy, tolerability, safety/toxicity, drug interactions, ease of use, and cost-effectiveness are essential factors that guide the selection of an adjuvant analgesic. Cost-effectiveness data are absent for the vast majority of these drugs. Pharmacological treatments should be used as part of a multimodal therapeutic programme for the management of neuropathic pain.