How long does methotrexate stay in your body for?

It lasts. @ and one half months for it and its polyglutamates to leave your body. We tell women desiring pregnancy to wait for three months.
Depends on… Dose & how long you were on it. Mtx's half life (amount of time for active med to be reduced by 1/2) is given as 3-15 hours but varies according the dose. It takes at least 4-5 half lives for a drug to be eliminated from the system, assuming there is normal liver & kidney function.