Diazepam levels in the ventricular cerebrospinal fluid and peripheral venous blood in man

: Six samples of ventricular cerebral spinal fluid from an external ventricular drain, and peripheral venous blood were taken during the course of parenteral diazepam administration in man. The diazepam level was measured by gas phase chromatography. The levels of diazepam in the CSF were low compared with the plasms concentrations and around the same level as the free circulating fraction. The drug appears in the CSF relatively late after intravenous administration. It would appear that the passage of the drug from the blood into the CSF is slow and not very marked. Therefore it is not the main cause for the pharmocodynamic effects which are the result of the drug passing the blood barrier in the more restricted sense.