How long can a vial of Methotrexate with preservatives be used after seal is broken?

Please let us know what form the Methotexate you are using is: intravenous, intramuscular, or subcutaneous (liquid, oil based, liquid). In a dark location at standard room temperature 66-74 degree F, even with a broken seal if it's a multi-dose vial the liquid should last in effectiveness for up to a year and the oil for up to two (though the FDA recommends discarding of any medication older than a year old). However, anything you are going to be injecting must also be considered for cross-contamination with airborne bacteria and illnesses. The liquid is most susceptible to contamination, the oil slightly less so. Because all forms are usually multi-dose vials when given for at home use (actually, at the Drs as well) even without the seal the pharma-demal (made up word) layer (the grey, black, green, or beige portion you insert the needle into to remove a quantity) will protect a conscientious individual from having to concern themselves with this possibility.

If you've located a single dose vial version (something I've never heard of), once it's exposed to the air the liquid should be used in no more than 2 weeks, and oil a month. Always check for cloudiness or particulate matter in liquid and oil based injectables before administration.