Systemic Local Anesthetics
Systemic administration of local anesthetics has been used to treat neuropathic pain syndrome. Clinical trials have provided some evidences that lidocaine and mexiletine are superior to placebo in this regard, Intravenous lidocaine is used for the treatment of neuropathic pain as a second-line therapy. If a patient has a positive response to IV lidocaine therapy, a trial of oral mexiletine may be considered.
However, mexiletine has a relatively high rate of adverse effects such as nausea, vomiting, tremor, dizziness, unsteadiness, and paresthesias. Given the limited number of supportive studies, mexiletine and other oral local anesthetics should only be used as second-line agents for neuropathic pain that has failed to respond to anticonvulsants or antidepressants.