i have been tested on a breathalyzer after having methotrexate and a small amount of alcohol and recorded a positive reading above .05 , a week later i was tested again ,bac readings without alcohol and the reading was .014 after taking the meds .10 mg dose.
conclusion depending on the dosage of methotrexate you will have a bac level of between .001 and .02 within 1 to 2 hours of taking the meds.