Cancer treatment by methotrexate: rational use following pharmacokinetic study

We used the test-dose method to calculate the dose of methotrexate to administer to the patients to reach the therapeutic but non-toxic blood concentration of 10(-5) mol/L. Methotrexate was tested with a radioimmunoassay technique and in 19 out of 20 patients we obtained the desired plateau during 24-h infusion.