Biomedical subjects

M J Norberto

Publications and source records attributed to M J Norberto.

3 recordsLinked to original sources

PubMed2001

Determination of clozapine and its N-desmethyl metabolite by high-performance liquid chromatography with ultraviolet detection.

A rapid high-performance liquid chromatographic method has been developed for the simultaneous determination of the atypical antipsychotic drug clozapine and its principal metabolite, N-desmethyl clozapine in human plasma. After liquid-liquid extraction the compounds were separated in a reversed-phase column and measured by ultraviolet absorption at 230 nm. For both compounds inter-day variations were <3.8%, and, based on a plasma sample volume of 2 ml, the limits of quantification were 25 ng/ml. Analytical interference from coadministered psychoactive drugs and their metabolites was also studied, and no interference was found from the most commonly used antidepressants and antipsychotic drugs. The assay is sufficiently sensitive and easy to use for the analysis of plasma samples in human clinical trials and therapeutic drug monitoring.

Antipsychotic Agents↗

PubMed2001

[Optimizing pharmacologic therapy for the elderly].

The authors analyze the most important aspects one should bear in mind regarding medication in elderly patients. The authors study the pharmaco-kinetic and pharmaco-dynamic changes which occur with aging and how these influence variations in therapeutic responses and their most frequent adverse reactions among the elderly. The authors conclude that it is necessary to draw up individualized therapeutic plans for these patients. The authors also analyze the general recommendations made for administering and prescribing medications for the elderly. Considering that the administration of medication and the evaluation of adverse reactions are some of the most important responsibilities nurses have, the authors recommend specific programs be drawn up to evaluate the efficiency-risk binomial and to keep a close watch on adverse reactions in these patients.

Aged↗

PubMed2000

Use of the mesoridazine/thioridazine ratio as a marker for CYP2D6 enzyme activity.

Thioridazine is metabolized in humans by CYP2D6 to mesoridazine, which is an active metabolite. Two or more CYP2D6 substrates are seldom given simultaneously to elderly patients because potentially dangerous metabolic interactions may occur. It may be valuable to know the CYP2D6 metabolic capacity of such patients to avoid drug interactions, which depend on the metabolic phenotype. The goal of this study was to evaluate the use of the mesoridazine/thioridazine ratio for the estimation of CYP2D6 enzyme capacity. A sensitive and reliable method has been developed for the determination of thioridazine and its metabolites, mesoridazine and sulforidazine. Commonly used central nervous system (CNS) comedications do not interfere with the method. A group of 27 chronic patients with mental illness receiving monotherapy with thioridazine were studied. There were 23 men and 4 women between 37 and 80 years old (mean +/- SD: 61.2 +/- 10.2). The thioridazine/mesoridazine ratio correlated with the debrisoquine metabolic ratio (r = 0.74, p < 0.001). Therefore, the authors suggest that the measurement of thioridazine and its metabolite might be a useful tool to assess CYP2D6 activity during treatment.

Adult↗