Effect of premedication on the induction dose of thiopentone in children.

The effective dose of thiopentone in 90% ( ED90 ) of unpremedicated children is 10.5 mg/kg. This is significantly greater (p less than 0.01) than in premedicated children. The ED90 in children premedicated with TDP (a mixture of trimeprazine , droperidol and physeptone with atropine) is 4.2 mg/kg which is significantly less (p less than 0.05) than with trimeprazine and atropine ( ED90 5.2 mg/kg) or papaveretum and hyoscine ( ED90 5.0 mg/kg).