Severity of deliberate acute baclofen poisoning: a nonconcurrent cohort study

Interest in high-dose baclofen treatment for alcohol dependence has increased over the past few years. In the meantime, the rate of acute baclofen poisoning has increased and life-threatening cases have been reported. Thus, severity of acute poisoning could lessen the benefit of baclofen treatment. Our aim was to evaluate the severity of acute baclofen poisoning independently of confounders and to assess whether severity is correlated with the reported ingested dose. We prospectively included consecutive patients with acute and deliberate baclofen overdose and compared them with gender and age-matched patients from a retrospective cohort of common acute medicine self-poisoning. The primary end-point was the adjusted risk ratio of mechanical ventilation. We also analysed the lengths of mechanical ventilation and risks of aspiration pneumonitis and convulsions. We finally examined the correlation between the supposed reported ingested dose and the severity of poisoning. Fourteen baclofen-poisoned patients were included and matched to 56 poisoned patients. Median age was 45 y/o (40-58), and men comprised 43% of patients. In logistic regression, the adjusted risk ratio of mechanical ventilation was 7.9 (1.4-43.5; p=0.02) for baclofen-treated patients. Aspiration pneumonitis was more frequent in baclofen-treated patients (29% versus 2%; p=0.005), and the length of mechanical ventilation was significantly correlated with the reported ingested dose of baclofen (Spearman coefficients: 0.48; p<0.001). Our results show that acute baclofen poisoning is more severe than other acute medicine overdoses, and severity seems to be correlated with the ingested dose of baclofen. These results raise some questions about the safety of high-dose baclofen treatment for alcohol dependence.