A randomized clinical study of a calcium-entry blocker (lidoflazine) in the treatment of comatose survivors of cardiac arrest. Brain Resuscitation Clinical Trial II Study Group BACKGROUND. Abnormalities of cellular calcium homeostasis have been implicated in the pathophysiology of postischemic encephalopathy. Calcium-entry-blocking drugs inhibit the influx of calcium into cells and have been shown to mitigate postischemic encephalopathy in animal models. METHODS. Five hundred twenty patients with cardiac arrest who remained comatose after the restoration of spontaneous circulation were randomly assigned to receive three doses of lidoflazine, an experimental calcium-entry blocker, or a placebo and were followed for six months. Four patients were lost to follow-up. Treated patients received an intravenous loading dose (1 mg per kilogram of body weight) of lidoflazine and two subsequent doses (0.25 mg per kilogram) 8 and 16 hours after resuscitation. The investigators were blinded to treatment assignment. RESULTS. There was no statistically significant difference between the lidoflazine group (n = 259) and the placebo group (n = 257) in the proportion of patients who died during the six-month follow-up (82 vs. 83 percent), who survived with good cerebral recovery (15 vs. 13 percent), or who survived with severe neurologic deficit (1.2 vs. 1.9 percent). Analysis of the best level of recovery achieved at any time during follow-up also did not show a difference between the treatment groups: 24 percent of those given lidoflazine and 23 percent of those given placebo recovered good cerebral function (normal or only moderately disabled cerebral performance) at some time. CONCLUSIONS. The administration of lidoflazine after cardiac arrest was not found to be beneficial. Our data do not support the routine use of this calcium-entry-blocking drug in comatose survivors of cardiac arrest. 