Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Mais filtros










Tipo de estudo
Intervalo de ano de publicação
1.
Ther Drug Monit ; 37(6): 733-44, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25853922

RESUMO

OBJECTIVE: In view of the large variability on therapeutic response and the multiple factors associated to tamoxifen (TAM) metabolic activation, this study aimed to evaluate the effect of CYP2D6 and CYP3A4 phenotypes, drug interactions, and vitamin D exposure on TAM metabolism in a group of breast cancer patients. METHODS: Trough blood samples were collected from 116 patients. TAM and metabolites endoxifen (EDF), N-desmethyltamoxifen, and 4-hydroxytamoxifen (HTF) were measured in plasma by liquid chromatography-tandem mass spectrometry. CYP2D6 and CYP3A4 phenotyping were obtained according to [dextromethorphan]/[dextrorphan] and [omeprazole]/[omeprazole sulfone] metabolic ratios, measured by high-performance liquid chromatography in plasma collected 3 hours after oral administration of 33 mg of dextromethorphan and 20 mg of omeprazole. Vitamin D3 was measured in plasma by high-performance liquid chromatography-ultraviolet. Data on concomitant use of drug considered as CYP2D6 and CYP3A4 inhibitor or inducer and vitamin D supplementation were recorded. RESULTS: About 20% of patients had reduced CYP2D6 metabolic activity and 7% CYP3A4 impaired metabolism. EDF levels diminished proportionally to the reduction of CYP2D6 metabolic activity (poor metabolizer 2.79 ng·mL, intermediate metabolizer (IM) 5.36 ng·mL, and extensive metabolizer 10.65 ng·mL, P < 0.01). Median plasma levels of TAM (161.50 ng·mL) and HTF (1.32 ng·mL) in CYP2D6 IM/CYP3A4 poor metabolizer patients were higher (P < 0.05) than those from CYP2D6 IM/CYP3A4 extensive metabolizer patients (122.07 ng·mL and 0.61 ng·mL, respectively). Seasons contributed to the interpatient variability of EDF and HTF levels; summer concentrations were 24% and 42% higher compared with winter. Vitamin D3 was not associated to CYP3A4 metabolic activity, indicating that other mechanisms might be involved in the relation between TAM metabolism and vitamin D exposure. CONCLUSIONS: CYP3A4 contributes to the bioactivation of TAM through formation of HTF and becomes increasingly important in case of reduced or absent CYP2D6 activity. EDF and HTF exposure were associated to seasonal variations, with considerable higher plasma concentrations during summer.


Assuntos
Antineoplásicos Hormonais/farmacocinética , Citocromo P-450 CYP2D6/genética , Citocromo P-450 CYP3A/genética , Tamoxifeno/farmacocinética , Adulto , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos Hormonais/administração & dosagem , Antineoplásicos Hormonais/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Cromatografia Líquida de Alta Pressão/métodos , Interações de Medicamentos , Feminino , Humanos , Pessoa de Meia-Idade , Fenótipo , Tamoxifeno/administração & dosagem , Tamoxifeno/análogos & derivados , Tamoxifeno/uso terapêutico , Espectrometria de Massas em Tandem/métodos , Vitamina D/sangue
2.
Rev. bras. mastologia ; 6(3): 144-8, dez. 1996. ilus
Artigo em Português | LILACS | ID: lil-208809

RESUMO

A gigantomastia é um desenvolvimento anormal e rápido da glândula mamária, de grandes proporçöes e de etiologia desconhecida, mais observada na mulher jovem, que pode ocorrer durante a gravidez ou adolescência. Säo relatados quatro casos diagnosticados no Serviço de Mastologia do Hospital de Clínicas de Porto Alegre, no período de 1985 a 1995. Além de caracterizar melhor esta patologia, que causa grandes transtornos de ordem física e psicológica, os autores destacam os aspectos do diagnóstico, complicaçöes, tratamento e associaçäo com outras enfermidades.


Assuntos
Humanos , Feminino , Adulto , Adolescente , Doenças Mamárias/cirurgia , Gigantismo/cirurgia , Mamoplastia , Mama/patologia , Hiperplasia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA