Biomedical subjects
P Munzenberger
Publications and source records attributed to P Munzenberger.
Evaluation of Ames Seralyzer for the therapeutic drug monitoring of phenobarbital and phenytoin.
Comparison of a reflective photometry assay (Ames Seralyzer) and a fluorescence polarization immunoassay (Abbott TDx) for measuring phenobarbital and phenytoin serum concentration was performed. Routine phenobarbital and phenytoin plasma levels drawn from patients in the pediatric neurology clinic and pediatric intensive care unit were determined in duplicate by the Abbott TDx and Ames Seralyzer systems. A total of 40 samples were assayed. The interday and intraday variability of the Ames system was determined using calibrators of known concentrations (5-25 micrograms/ml). There was significant correlation between the serum phenobarbital or phenytoin concentrations when determined by the Seralyzer and TDx systems. The intraday variability for the measurement of phenytoin when determined by the Seralyzer had coefficients of variation ranging from 2.2 to 8.9%. The interday variability for phenytoin when measured by both the TDx and the Seralyzer correlated well with known calibrators. The utility of the Ames Seralyzer for acute-care facilities, physician offices, and pharmacy satellites is apparent. Based on statistical analysis, the Seralyzer provides accurate phenobarbital and phenytoin serum measurements for clinical use in therapeutic drug monitoring.
Evaluation of the Ames Seralyzer for therapeutic drug monitoring of phenobarbital and phenytoin.
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Comparison of the Seralyzer and EMIT systems for determination of theophylline concentrations.
A reflectance photometry assay for measurement of serum theophylline concentration was evaluated by comparison with an enzyme-multiplied immunoassay technique (EMIT). The concentration of theophylline in blood samples obtained from patients receiving intravenous theophylline therapy in the pediatric intensive-care unit was measured by both the Seralyzer and the EMIT systems. The interday and intraday variability of each method were also determined by means of calibrators of known concentration (5 to 40 micrograms/mL). There was significant correlation between the serum theophylline concentrations determined by the Seralyzer system and the EMIT system. The overall standard error of the estimate was 2.3 micrograms/mL, but with operator experience this improved to 1.3 micrograms/mL. Intraday variability was 1.2 micrograms/mL for the Seralyzer and 0.7 micrograms/mL for EMIT; the respective values for interday variability were 1.4 micrograms/mL and 0.8 micrograms/mL. The Seralyzer method measures theophylline concentrations with reliability, convenience, and speed. It could be potentially useful in a satellite, clinic, or acute-care pharmacy area.
The role of a pharmacist on the pediatric unit of a general hospital.
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The incidence of drug-diagnostic test interferences in outpatients.
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Severe withdrawal syndrome possibly associated with cessation of a midazolam and fentanyl infusion.
A 40-month-old child was sedated with a fentanyl and midazolam infusion for 7 days. After the drugs were discontinued he became unresponsive and globally aphasic, and had marked thrombocytosis. He was hospitalized for 4 weeks, during which time his motor and cognitive status slowly improved, and had almost returned to baseline at time of discharge. Severe neurologic abnormalities have been reported with midazolam and fentanyl, administered separately or together, and seem to be a consequence of a withdrawal syndrome. Of interest, this patient had a reactive thrombocytosis at the time of onset of the withdrawal syndrome, and his decreased platelet count coincided with the return to normal cognitive and motor status. Based on this experience and other reports, we believe midazolam-fentanyl combination should be administered with caution.