The influence of biperiden in overdose on respiration and circulation in the dog.

Biperiden lactate was administered intravenously in overdose to dogs under general anaesthesia. Biperiden appeared to have a toxic influence on respiration and circulation independently. Respiratory arrest occurred at a dose of 33 +/- 10 mg/kg and has probably a central origin. When artificial ventilation was instituted circulatory standstill occurred at a dose of 45 +/- 5 mg/kg. The toxic influence of biperiden is characterised by a decrease of heart rate and of left ventricular contractility resulting in cardiogenic shock. Biperiden is compared with orphenadrine as far as its potential hazard is concerned for patients trying to commit suicide by ingesting an overdose.