Opioids Flashcards
Opioids
relieve moderate to severe pain
Nociceptors
pain receptors
afferent neurons in the ascending pathway
A-delta Fibers
large diameter, sparsely myelinated
evokes sharp, well localized pain- somatic
C Fibers
small diameter, unmyelinated
makes aching, poorly localized pain- visceral
Neurotransmitters of the descending pathway
norepinephrine
serotonin
inhibit ascending pain pathway
Delta Receptors Locations
widely throughout CNS
in some peripheral tissues
Mu Receptors Locations
B- Endorphin in hypothalamus
anterior lobe of pituitary
K receptors Locations
hypothalamus
posterior lobe of pituitary gland
Opioid receptors are coupled to…..
adenylyl cyclase and G-proteins
Functions of Mu and Delta Receptors
sedation
Opioid Action at Presynaptic Level
closes voltage gated Ca channels to inhibit neurotransmitter release
Morphine Receptors
Mu
Mixed Action Opioid Receptors
K receptors
Used to control pain in Keratitis
codeine, oxycodone, hydrocodone, pentazocine, tramadol
Opioids and Fetus
can cross placental barrier
causes respiratory depression and physical dependents
Active metabolite of morphine
morphine-6-glucuronide
Condition increasing the half life of opioids
liver disease
Most analgesic and euphoric opioids
oxycodone
Side Effects of Opioids
cough suppresion constipation orthostatic hypotension reduced libido, urinary retention blurred vision, miosis, diplopia
Classic Triplet of Opioid Toxicity
pinpoint pupils
respiratory depression
coma
Opioid Withdrawal
mydriasis, chills, hyperventilation, diarrhea, anxiety
Treating Heroin Addiction
Methadone
Naltrexone
Monoamine Oxidase Inhibitors
contraindications of all opioids
causes hyperpyrexia coma and hypertension
Uses during Acute Pain
strong agonists- fentanyl and morphine
IV
Uses during less severe and chronic pain
moderate agonists
oral
Strong Agonists
Morphine
Moderate Agonists
Codeine, Oxycodone, Hydrocodone
Partial Agonists
Burprenorphine
Mixed Agonists-Antagonists
Pentazocine
Full Antagonists
Nalaxone
Managing Acute Pulmonary Edema
morphine
Methadone
used in maintenance of opiate addiction and withdrawal
Codeine
cough suppressant
analgesia
used in combo with NSAIDs
Naltrexone
decreases desire for alcohol
opiate addiction
Methylnaltrexone
treatment of opioid induced constipation
