RESUMEN
In 29 patients, 21 suffering from psoriatic arthritis and eight patients suffering from rheumatoid arthritis, methotrexate serum-levels were determined by means of radioimmunoassay. The aim of the investigation was to recognize an eventual dependence of the serum level of methotrexate on the total cumulative dose and to test the possibility of a concomitant therapy control. Beside the determinations of the serum levels of methotrexate, clinical examinations and laboratory tests were done at regular intervals. The values obtained showed no significant increase during the course of therapy compared to the values at the beginning of the treatment. Likewise no correlation to the total cumulative dose, the clinical picture or to the occurrence of side-effects could be found. Nor could any relationship between the changing of laboratory parameters and the methotrexate serum-levels be observed. No differences appeared in the methotrexate serum-levels during therapy of either rheumatoid or psoriatic arthritis patients. In conclusion it seems impossible to monitor a low-dose methotrexate therapy by continuous determinations of the serum levels of the drug.
Asunto(s)
Artritis Reumatoide/tratamiento farmacológico , Metotrexato/sangre , Psoriasis/tratamiento farmacológico , Artritis Reumatoide/sangre , Proteína C-Reactiva/análisis , Espectroscopía de Resonancia por Spin del Electrón , Femenino , Humanos , Inyecciones Intravenosas , Masculino , Metotrexato/efectos adversos , Metotrexato/uso terapéutico , Persona de Mediana Edad , Psoriasis/sangreRESUMEN
To verify the possibility of a concomitant therapy control in 31 patients (18 psoriatic arthritis [PA], 13 rheumatoid arthritis [RA]) the blood cell concentration of Methotrexate (MTX) was continuously measured over a period of 6 months. The determinations were carried out by using a RIA of the CIS Corp. At any time MTX was determined laboratory and clinical examinations were done and the P-III-P serum-level was measured by using a RIA of the Behringwerke. The cellular MTX showed to be statistically significantly elevated compared to baseline, whereas within ranges of total cumulative dosages only insignificant fluctuations could be noticed. Like in the treatment of Psoriasis a strict correlation between the weekly administered dose and the cellular MTX could be established, the total cumulative dose, however, had no influence on the cellular MTX-level. In the treatment of RA slightly higher weekly dosages were necessary, which caused significantly higher cellular MTX concentrations in RA patients. Some correlations between clinical as well as serological parameters of disease activity could be noticed, nevertheless they do not allow distinct interpretations. In both diseases a significant relationship between the cellular MTX-level and the P-III-P serum-level could be realized. A storage of MTX in blood cells, especially in erythrocytes, seems to be evident. To reach therapeutical benefit in RA slightly higher mean dosages may be necessary. A therapy monitoring by the means of continuous determinations of cellular MTX seems to be impossible. In contrast an approach to the early detection of liver fibrosis can be given by the correlation between cellular MTX and the P-III-P serum levels.