Toxicity potential of oral lidocaine in a patient receiving mexiletine.
OBJECTIVE
To report a case of toxicity from orally administered lidocaine in a patient with cardiomyopathy receiving concurrent mexiletine therapy.


METHODS
Case reports, review articles, and studies identified by search of the MEDLINE database and Current Contents.


METHODS
All reports of toxicity from orally administered lidocaine were reviewed.


RESULTS
Lidocaine, a local anesthetic, is widely used to treat cardiac arrhythmias. Toxicity with the parenteral form occurs frequently. In contrast, there are few reports of toxicity with oral lidocaine, most of them occurring in children receiving large doses relative to body weight. We report a case of intoxication in an adult with severe cardiomyopathy and concurrent mexiletine therapy who received only two doses of oral lidocaine.


CONCLUSIONS
Although it is rarely reported in adults, clinicians must be alert to the possibility of toxicity from orally administered lidocaine. This is most likely to occur in patients with conditions known to reduce lidocaine clearance, when higher-than-usual doses are administered, or when concurrent therapy with oral lidocaine analogs may be present.
Geraets
D R
DR
College of Pharmacy, University of Iowa, Iowa City 52242.
Scott
S D
SD
Ballew
K A
KA
D000284:Administration, Oral; D002311:Cardiomyopathy, Dilated / Q000188:drug therapy; D002490:Central Nervous System / Q000187:drug effects; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage / Q000506:poisoning*; D008801:Mexiletine / Q000008:administration & dosage* / Q000627:therapeutic use; D008875:Middle Aged
D008801:Mexiletine; D008012:Lidocaine