Prophylactic lidocaine: uncertain benefits in emergency settings.

The need to determine whether prophylactic lidocaine has any therapeutic value is generally recognized, and further investigations have been urged: A carefully designed clinical trial of routine lidocaine administration should be carried out to provide definitive information for the physician treating patients who have had myocardial infarction. Such trials should begin immediately, in view of the magnitude of the problem and the fact that routine prophylaxis of arrhythmias after myocardial infarction is not common policy. Such a study, if well designed, can answer the question... Carefully designed trials must be conducted with patients included in the study as soon as possible after the onset of symptoms, preferably during the prehospital phase, and the medication must be administered in a random-controlled fashion. Although these requirements pose no extraordinary problems of research design and method, they lead to prohibiting ethical conflicts. Without resolving these conflicts, through the elaboration of acceptable standards which bypass traditional informed consent, the value of lidocaine prophylaxis will remain uncertain, as will the many other emergency therapeutic maneuvers of unproven effectiveness.