Pedro Kurtz, Anna Beatriz Ribeiro Elias, Guilherme Suarez-Kurtz
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引用次数: 0
Abstract
Aims: To investigate the association of CYP2C9 metabolic phenotypes with phenytoin plasma concentration ([PTH]) in neurosurgical patients from the Brazilian Public Health System.
Methods: Patients (n = 170) were treated with phenytoin (300 mg/day) perioperatively as prophylaxis for postoperative seizures. Two to 10 days after surgery, a blood sample was collected for quantification of [PTH] and genotyping of CYP2C9*2 and *3 alleles. CYP2C9 metabolic phenotypes, NM (normal), IM (intermediate), and PM (poor) metabolizer, were inferred from CYP2C9 diplotypes. Linear regression modeling was applied to identify predictors of [PTH].
Results: Wide (22-fold) interindividual variation in [PTH] was observed (2.2-47.5 mg/l). [PTH] associated significantly (Kruskal-Wallis P < 0.005) with CYP2C9 phenotypes and there was a significant trend (Jonckheere-Terpstra test, P < 0.0001) for [PTH] increase in the order NM < IM < PM. [PTH] was within the target therapeutic range (10-20 mg/l) in 34.7% of patients, while 39.4% and 25.9% had [PTH] below and above the range, respectively. CYP2C9 phenotypes associated significantly (chi-square P = 0.004) with the distribution of patients in [PHT] therapeutic categories and the Cramér's V test pointed to moderate magnitude of the effect of CYP2C9 phenotypes (V = 0.211).
Conclusion: Diplotype-predicted CYP2C9 metabolic phenotypes are associated significantly with [PTH] in neurosurgical Brazilian patients receiving phenytoin for postsurgery seizure prophylaxis. [PHT] increased progressively in the phenotype order NM < IM < PM, and all PM patients had [PHT] above the target therapeutic range, consistent with the CPIC guideline 'strong' recommendation for phenytoin dosing adjustments in PMs.
期刊介绍:
Pharmacogenetics and Genomics is devoted to the rapid publication of research papers, brief review articles and short communications on genetic determinants in response to drugs and other chemicals in humans and animals. The Journal brings together papers from the entire spectrum of biomedical research and science, including biochemistry, bioinformatics, clinical pharmacology, clinical pharmacy, epidemiology, genetics, genomics, molecular biology, pharmacology, pharmaceutical sciences, and toxicology. Under a single cover, the Journal provides a forum for all aspects of the genetics and genomics of host response to exogenous chemicals: from the gene to the clinic.