Opioids

Commonly Used Opioids

Opioid	Dose	Onset	Duration	Elimination	Unique effects/indications
Fentanyl	1-20 ug/kg	4-6 min	30-45 min	Hepatic	Not used as infusion
Sufentanyl	0.3-1 ug/kg	1-2 min	20-40 min	Hepatic	...
Remifentanyl	0.3-1 ug/kg	1-1.5 min	5-10 min	Plasma esterases, context sensitive half-life	Profound hypotension/bradycardia, "MAC sparing" reduces need for other anesthetics by 75%
Alfentanyl	5-50 ug/kg	1-2 min	20 min	Hepatic	...
Morphine sulfate	25-75 mg	10-30 min	2-5 hrs	Hepatic	Can cause histamine release
Meperidine	Example	10-30 min	2-5 hrs	Hepatic	Used for post-op shivering, can't give to patients taking MAOIs

• Don’t combine benzodiazepines and opioids. If you need to reverse, use flumazenil.
• Central loci of opioid action (descending inhibitory pain pathways)
  • PAG
  • Nucleus Raphe magnus
  • Rostral ventromedial medulla

Short-Acting

• Oxycodone, Hydromorphone, Morphine
• Morphine can cause rash/pruritis

Long-Acting

• Oxycodone ER = OxyContin
• Methadone
• Fentanyl is really only used intra-op or in palliative care.