If i took 1 mg xanax (alprazolam) on thues at 3am and never have taken one before will i pass a drug test on friday at 3pm?

Depends...: Depends on how long the xanax (alprazolam) stays in your system, which can vary from person to person. The half-life 6.3 to 26.9 hours. It can take 5.5 half lives for a drug to be eliminated from your system entirely, so that means that xanax (alprazolam) might be detectable as long as 147.95 hours which translates to 6 days. So if Thues = Tuesday and your test is on that Friday it "could" still be detected.