Blood levels of diazepam after endotracheal administration in dogs

A pilot study was performed to evaluate the endotracheal administration of diazepam. Five mongrel dogs were anesthetized and orotracheally intubated. Diazepam in a dose of 0.5 mg/kg was delivered through a red rubber catheter placed through the endotracheal tube. Diazepam levels were then measured at 0, 30, and 60 seconds, and at 2, 5, 15, 30, and 60 minutes. Arterial blood gas determinations were performed at 0, 10, 30, 60, and 90 minutes. In all dogs peak serum levels averaged 1,500 ng/ml +/- 541 ng/ml, which is well above therapeutic anticonvulsant levels (150 ng/ml to 600 ng/ml). Arterial pH an PCO2 did not change dramatically from control values during the period of study. Arterial PO2 showed a transient drop of approximately 10 to 30 mm Hg within the first 60 minutes, but returned nearer the control values by the end of 90 minutes. the endotracheal administration of diazepam has been shown to be effective in achieving rapid therapeutic serum levels of the drug. Further study is needed to determine any deleterious effects on the lungs before this method of administration can be recommended for use in humans.