PLASMA-CONCENTRATIONS OF MIDAZOLAM AFTER .4. NASAL OR RECTAL ADMINISTRATION IN CHILDREN

Midazolam is used frequently for premedication in children, preferably by non-parenteral administration. We have compared plasma concentrati ons of midazolam after nasal, rectal and i. v. administration in 45 ch ildren (aged 2-9 yr; weight 10-30 kg) undergoing minor urological surg ery. General anaesthesia consisted of spontaneous respiration of halot hane and nitrous oxide in oxygen via a face mask. After administration of atropine and fentanyl iv., children were allocated randomly to rec eive midazolam 0.2 mg kg-1 by the nasal, rectal or iv. route. In the n asal group, children received 50% of the dose of midazolam in each nos tril. In the rectal group, midazolam was given rectally via a cannula. Venous blood samples were obtained before and up to 360 min after adm inistration of the drug. Plasma concentrations of midazolam were measu red by gas chromatography and electron capture detection. After nasal and rectal administration, midazolam Cmax was 182 (SD 57) ng ml-1 with in 12.6 (5.9) min, and 48 (16) ng ml-1 within 12.1 (6.4) min, respecti vely. Rectal administration resulted in smaller plasma concentrations. In the nasal group, a plasma concentration of midazolam 100 ng ml-1 o ccurred at about 6 min. After 45 min, the concentration curves after i . v. and nasal midazolam were similar.