Yeah that's right. It wears off in about 60-90 minutes. Many of the commonly taken opioids (especially if taken orally) last much longer than that, so if the pe

Yeah that's right. It wears off in about 60-90 minutes. Many of the commonly taken opioids (especially if taken orally) last much longer than that, so if the person experienced a severe overdose it's a good idea to monitor them for the duration (or even just administer small does at regular intervals). However, much of this depends on the initial route of administration. Intravenous would probably wear of the quickest. For fentanyl, Wikipedia says 30-60 mins, but that's at 'medically useful' dosage levels from what I can tell (remember, not all drugs are metabolised in a time-linear fashion). I'd assume insuffilated Naloxone would last the longest, followed by intra-muscular and finally intravenous. And the inverse would be true regarding how long they would take to have an effect. I don't think taking it orally is a viable option for OD, as it would take much longer to have an effect, and much of it would be destroyed by your first-pass metabolism. And yeah, me and apostrophes have not been getting along very well lately...