Therapeutic drug monitoring
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This case report describes a false-positive amphetamine/ecstasy [3,4-methylenedioxymethamphetamine (MDMA)] and ecstasy (MDMA) screen after therapeutic use of antihyperlipidemic drug, fenofibrate. A 60-year-old male patient was admitted to inpatient psychiatry unit with the diagnosis of alcohol dependency. He was prescribed diazepam 30 mg/day, thiamine 300 mg/day, and naltrexone 50 mg/day. ⋯ After discontinuation of fenofibrate, amphetamine/MDMA, and MDMA immunoassay results turned out to be negative. Caution should be given to interpretation of amphetamine/MDMA (CEDIA) and MDMA (DRI) tests in patients taking fenofibrate. Specific confirmation with a suitable method should be used to prevent erroneous interpretations.
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Multicenter Study
Minimization of the preanalytical error in pharmacokinetic analyses and therapeutic drug monitoring: focus on IV drug administration.
The conduct of multicenter pharmacokinetic (PK) analyses for long-established drugs entails specific problems, because samples have to be obtained within daily clinical practice. Practices for intravenous (IV) drug administration vary between hospitals, including the use of different infusion devices, the use of infusion line systems with different line volumes, and different priming and rinsing procedures. ⋯ The choice of the infusion apparatus, standardized infusion systems, and standardized operating procedures for drug administration are important when performing postmarketing PK analyses in multicentric studies.
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Critical illness is a major determinant of midazolam clearance in children aged 1 month to 17 years.
In children, a large variability in pharmacokinetics of midazolam, a cytochrome P450 3A4/5 (CYP3A4/5) enzyme substrate, has been described, which cannot be explained by age-related changes alone. In this study, these age-related changes are studied in relation to other covariates to explain the variability in the pharmacokinetics of midazolam in children. ⋯ From infancy to adolescence, critical illness seems to be a major determinant of midazolam clearance, which may result from reduced CYP3A4/5 activity due to inflammation. This may have important implications for dosing of midazolam and other CYP3A drug substrates in critically ill children.
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Codeine is an old and commonly used analgesic agent for mild to moderate pain. It is the prototypical "prodrug" in that its analgesic effect is almost wholly dependent on its biotransformation to morphine, a process that is mediated by the polymorphic cytochrome P450 2D6 enzyme. ⋯ This review will discuss the relative role of pharmacogenetics and therapeutic drug monitoring in predicting and/or maintaining adequate and safe analgesia with codeine. The review will end on a discussion of how the marriage of these 2 fields may provide new insights into the mechanisms of codeine-induced toxicity and analgesia.