I bought green coffee premium 1 yr ago , is it expired now and what is the side effects of using such drug ?

Caffeine effects: You should be able to find an expiration date somewhere on the bottle but I expect it is still good and safe to use even if a bit past the "expiration date" (which is generally not that accurate). The only side effect might be getting a bit hyper from the caffeine but it only has as much caffeine as 1/5 cup of coffee. See https://authoritynutrition.com/green-coffee-bean-extract-review/