I'm prescribed xanax (alprazolam) for panic attacks, and am wondering if it's safe to take xanax prior to receiving a moderna vaccine? and are there interactions between xanax and epinephrine (i don't have a history of allergies but want to be safe)?

There is absolutely no contraindication regarding vaccine when one is taking Xanax. If epinephrine were needed, which is exceeding rare, there would be no prohibition. Get your vaccine and protect yourself, as the bigger worry is COVID-19

There has been no reported and no known interaction between Xanax and Moderna Covid 19 vaccine. Suffice it to say that, with millions of people who received it in the past few months, such drug to drug interaction would have surfaced by now. That is not to say there will be none in the future but that the likelihood is not significant. Xanax sedates while Epinephrine does the opposite.