Characteristic toxidrome (PMID 22784117). Reversal with naloxone in approriate dosage and duration (PMID 22784117) is a key feature of opioid overdose or poisoning (PMID 26086633). See also under heroin, morphine, fentanyl and naloxone (PMID 22784117, 23066838, 23636734, 25102043). Synthetic opioids sold as natural products or incense can cause microepidemics of Zombie outbreaks, with fatal cases (PMID 27973993). Compounds can be difficult to trace in the laboratory (PMID 27973993). Can also cause severe bleeding when tainted/laced with superwarfain (PMID 30280655). See also under cannabinoids.