I can confirm his experience via my brother's nearly identical experience. He asked for a non-addictive painkiller, as he knows he has an addictive personality.

I can confirm his experience via my brother's nearly identical experience. He asked for a non-addictive painkiller, as he knows he has an addictive personality. He was prescribed an opiod anyway, I don't recall which, for a serious abscessed tooth. After a couple of days he was experiencing identical symptoms as the GP. I'm not trying to chime in on how strictly we're interpreting "instantly," but for me I will definitely do my best to avoid opiods. Taking the prescribed amount for 2-3 days, and literally not taking the rest of the pills (both GP and my brother), and having serious physical withdrawals--that's fast enough that I would rather avoid it.