Opioids Flashcards
Pain Impulse
Originates in tissues and nociceptors recognize/produce pain. Response is to release chemicals, send signal up spinal cord into brain. Thalamus is relay center that sends info to all different parts of the brain.
Response sends signal from brain, down spinal tracts, to periphery in order to respond
Mu-opioid receptor
B endorphin, met and leu enkephalins
Analgesia Euphoria/sedation Physical dependence Resp. Depression Constipation Miosis Urinary retention Bradycardia Pruritus Skeletal muscle rigidity Biliary spasm
Delta opioid receptor
Met and leu enkephalins
Physical dependence Analgesia Resp. Depression Constipation Urinary retention
Kappa opioid receptor
Dynorphins
Analgesia Dysphoria Low abuse potential Miosis Antishivering
How Opioids Work
When you give morphine, attaches to opiate receptors and decreases amount of pain chemicals released from presynaptic neuron (just like endorphins). Less binding to post synaptic neuron
Phenanthrenes
Morphine Codeine Hydrocodone Oxycodone Hydro or phone Butorphanol Nalbuphine
**histamine release!!! (And meperidine)
**cross allergy within class, not between
Piperidine
Meperidine (histamine release) Fentanyl Sufentanyl Alfentanyl Remifentanyl
Diphenylheptanes
Methadone
When to dose highest amount of opioids
At the beginning of the case when intubating and during skin incision
Need less for closing
CO2 response
Increased CO2/decreased response to CO2 d/t respiratory depression
Need higher amounts of CO2 to cause respiratory response
Cause Muscle Rigidity
Fentanyl and derivatives
Thought to be caused by dose of narcotic and speed of administration
Treat with succ
Miosis and Constipation
Never develop tolerance
Used for Antishivering effect
Meperidine (k receptor)
Biliary Pressure
Narcotics increase biliary pressure d/t vagal effect on sphincters.
Sphincter of Oddi is tightened (similar to urinary retention) causing bile/pressure build up and possible biliary colic
Treatment of increased biliary pressure
Atropine or glyco
Nitro
Glucagon
Naloxone
Opioid Antagonist
Naloxone (Narcan)
Codeine after tonsillectomy
Found out codeine is metabolized to morphine and there are genetic differences in the metabolism speed (faster metabolizers such as kids have higher morphine levels and more respiratory depression)
Opioid metabolism
In the liver, eliminated as conjugate (liver disease will prolong DOA)
Remifentanyl metabolism
Non-specific esterase hydrolysis
Meperidine toxicity
Metabolized to CNS toxic metabolite that can cause seizures (normeperedine)
Do not use>24 hours or for prolonged periods
Do not use in renal disease or the elderly
Meperidine and MAOIs
Adverse interaction causing seizures and severe cardiac effects that can lead to death
Codeine and Tramadol age limit
Contraindicated in kids<12
Serotonin Syndromes
Can develop when pt on SSRIs and some phenylpiperidines
