My Girlfriend Is Starting Chemo Tomorrow For Her Lupus, I'm

My girlfriend is starting chemo tomorrow for her lupus, I'm unsure as to exactly what her regiment will be but the three main ines seem to be cyclophosphamide, mycophenocate mofetil, and methotrexate. I also am pretty sure she smokes meth and didn't make her dr. Aware of it. Besides the normal things, should I worry about any other effects from mixing the chemo and meth?