Natural derivatives: Heroin, Morphine, Codeine, Hydrocodone, Oxycodone (+ UDS)
Synthetic: Fentanyl, Hydromorphone, Buprenorphine, Methadone, Meperidine, Dextromethorphan (- UDS)
Obtain acetaminophen levels in all cases of combination<unk> -acetaminophen (Percocet) overdoses
Respiratory depression is the cause of all mortality from<unk> 
When prescribing<unk>  pain relievers in the ED, remember to have a discussion of co-ingestion of other depressants (alcohol involved in 1/5 of<unk>  related deaths)
Consider contributing to the DAWN database for public ED research benefit (Drug Abuse Warning Network)
Other than common co-ingestions, consider adulterants such as amphetamines, anticholinergics, hypnotics, heavy metals, etc.
In the year after an ED visit for an<unk>  overdose, greater than 5% die & greater than 19% will experience another<unk>  overdose.
Opioid toxicity
Clonidine toxicity
Benzodiazepine toxicity
Organophosphate toxicity
Opioid withdrawal
CO poisoning
Marijuana toxicity
Hypoglycemia