I take mirtazapine 15mg and ambien (zolpidem) 10mg at bed time to sleep i was wondering if i desided to stop taking it what would be the best way to do so ?

Stop which one ?: First of all, Mirtazapine is an antidepressant . Don't stop taking it without discussing with your prescribing md. That said, if you are taking Mirtazapine you should sleep well enough that you would not need the ambien (zolpidem). So i will assume you want to go off ambien (zolpidem). Taper it. Lower it to 1/2 tab and see if you still sleep ok, then 1/4 tab, and if ok, then stop.