For neuropathic pain, there is evidence that the analgesic effect of intrav
enous sodium-channel blockers is robust and dose dependent. Oral agents are
less impressive, but efficacious nonetheless, especially at higher doses.
Despite the evidence from animal studies for a role of sodium channels in i
nflammatory hyperalgesia, the clinical evidence of analgesic effect of oral
and intravenous sodium channel blockers in both acute and chronic nonneuro
pathic pain is equivocal. The results to date from human experimental pain
models suggest a lack of effect of systemic lidocaine on acute nociceptive
pain and that the effect on cutaneous hyperalgesia is modest, at best. Furt
hermore, the literature suggests that the systemic lidocaine analgesia is b
oth dose and diagnosis dependent.