Incidence, causes and prognosis of hypotension related to meprobamate poisoning.

Objective: Meprobamate self-poisoning has been reported as potentially inducing hypotension. We examined the incidence and causes of hypotension induced by this poisoning and its prognosis.

Design And Setting: Retrospective observational study conducted in a medical ICU between June 1997 and October 2003. Seventy-four patients admitted for meprobamate poisoning and needing mechanical ventilation were included. Demographic, clinical, and laboratory data were compared between patients with and without hypotension. All echocardiograms recorded in patients with hypotension were reviewed, and left ventricular (LV) and right ventricular (RV) functions were assessed.

Results: Twenty-nine (40%) patients exhibited hypotension without any significant difference in age, gender, cardiac history, or meprobamate concentration in blood when compared to patients without hypotension. Base excess was significantly lower in patients with hypotension. Echocardiography demonstrated a hypokinetic state, associating decreased LV ejection fraction (45+/-15%) and cardiac index (2+/-0.7 l min(-1) m(-2)), and increased inferior vena cava diameter. Most patients with hypotension received inotropic drugs by infusion, and were ventilated for significantly longer.

Conclusions: Meprobamate self-poisoning induces hypotension, notably related to cardiac failure, in about 40% of cases. This has important therapeutic consequences, as frequent inotropic drug infusion. The mechanisms of cardiac toxicity remain largely unknown, and no predictive factor could be isolated.