Systemic local anesthetics in pain control.

Analgesia has been reported as a potential effect of systemically administered local anesthetics for over four decades. Interest in the use of these drugs as analgesics has been stimulated by the advent of oral formulations and the findings of several controlled studies that suggest efficacy of these preparations in neuropathic pain syndromes. We review the pharmacology of local anesthetics and critically evaluate the medical literature describing the analgesic consequences of systemic administration. The data extant support their analgesic effect in selected pain syndromes.