Plasma concentrations of midazolam in children following intranasal administration.

Nasally administered midazolam appears to be a useful method for rapidly sedating children prior to the induction of anesthesia. We determined the peak plasma concentrations after intranasal administration of midazolam and compared this to plasma concentrations achieved after intravenously administered midazolam in 18 children between the ages of 14 months and 5 yr, who underwent elective closure of an asymptomatic atrial septal or ventricular septal defect. Preanesthetic medication was at the discretion of the attending anesthesiologist. Induction of anesthesia was with halothane in N2O and O2 via mask, and tracheal intubation was performed after the administration of fentanyl or sufentanil plus pancuronium. Anesthesia was maintained with these agents, and augmented with halothane or isoflurane. As soon as arterial access was established, the patient received 0.1 mg/kg of either intranasal or intravenous midazolam. Midazolam concentrations were measured by gas chromatography-mass spectrometry. Intranasal midazolam achieved its peak plasma concentration of 72.2 +/- 27.3 ng/ml in 10.2 +/- 2 min. Ten minutes after the administration of midazolam, the mean plasma concentration in the intranasal midazolam group was 57% of the concentrations in the group receiving midazolam intravenously. These results confirm the clinical impression that intranasal administration of midazolam rapidly achieves sedative plasma concentrations in children.

Revaccination of previous recipients of killed measles vaccine: clinical and immunologic studies.

Clinical and immunologic studies were performed in association with revaccination with live measles vaccine in 75 adolescents 11 to 14 years after immunization with killed measles vaccine. Ten subjects had local pain with swelling or erythema or both at the injection site; in three, the local reactions were severe and disturbing systemic complaints were also noted. These marked reactions were more common in subjects in whom the interval between the last dose of killed vaccine and the dose of live vaccine of the primary immunization series was less than or equal to 2 months, in subjects with prevaccination serum HAI antibody titers of less than or equal to 5, and in subjects with high measles antigen specific lymphocyte stimulation ratios. Serum complement levels could not be correlated with clinical reactions. Measles specific lymphocyte stimulation ratios were significantly higher in recipients of killed vaccine than in three compara,ive groups, in subjects with a killed-live interval in the initial vaccine series of less than or equal to 2 months as compared with greater than or equal to 3 months, and in subjects with prevaccination HAI antibody titers of less than or equal to 5 as compared with titers greater than or equal to 10. Although both low serum antibody and high measles specific lymphocyte reactivity were associated with marked local reactions, and probably indicative of susceptibility to atypical measles, our findings suggest that exaggerated lymphocyte reactivity is of greater importance in the adverse clinical response.