Effect of flumazenil on the electroencephalogram of patients with portosystemic encephalopathy. Results of a double blind, randomised, placebo-controlled multicentre trial

Abstract

The efficacy of the benzodiazepine antagonist flumazenil has been assessed clinically in a double blind, randomised, placebo-controlled multicentre study in patients with grade I–III portosystemic encephalopathy. In an ancillary study reported here the effect of flumazenil on the electroencephalogram (EEG) was analysed in 32 patients who had EEG grading according to protocol. Following the baseline observation period, patients were randomised to receive (at 1 min interval) 3 sequential bolus injections of flumazenil (0.4, 0.8 and 1 mg) or placebo followed by infusions of flumazenil (1 mg/h) or placebo for 3 h. Patients were monitored for 5 h after infusion. A positive response was defined as 1 point improvement in EEG grade. After independent analysis of the EEG gradings 5 out of 17 (29%) flumazenil treated patients showed an improvement in EEG grading (3 after bolus, 2 during follow-up) compared to 2 out of 15 (13%) placebo treated patients (1 afterbolus, 1 during follow-up) (95% confidence interval of difference: −12% to +50%). Of the 5 EEG responders after flumazenil, 3 also had an improvement in clinical PSE grading (none after bolus, 2 during infusion, 1 during follow-up), compared to neither of the 2 EEG responders after placebo. EEG responders did not differ from non-responders with respect to Child-Pugh score, basal EEG, PSE grade and positivity for benzodiazepines. In conclusion, treatment perspectives for flumazenil in portosystemic encephalopathy appear to be present for only a minority of patients; however, this study yields no support for a major role of benzodiazepine antagonists in the treatment of hepatic encephalopathy.