Lecture 1 - Opiate (Morphine) Characteristics Flashcards
What is the MOA for morphine and effect of neurotransmitter release?
- Stimulates opiate receptors, GPCR decreases adenylate cyclase and decrease cAMP. Increases K+ efflux, decrease Ca2+ influx.
- decreases neuronal excitability and neurotransmitter release (glutamate, Ach, 5-HT, NE and substance P
What receptors does morphine act on the create its analgesic actions?
(Related to pain fiber pathway)
- Morphine acts on interneurons (integration synapses)
- decreases substaince P, the excitatory neurotransmitter in the pain pathway
Electrical stimulation of enkephalinergic neurons or acupuncture will cause analgesia.
TRUE/FALSE
TRUE
Describe unique characteristics of mu analgesic receptors
Analgesic and antidiarrheal are common to mu, kappa and delta receptors
- (spinal supraspinal and peripheral) respiratory depressant
- sedation
- euphoria
Describe unique characteristics of kappa analgesic receptors
Analgesic and antidiarrheal are common to mu, kappa and delta receptors
- diuresis
- psychotomimesis (mimics psychosis)
- sedation
Describe unique characteristics of delta analgesic receptors
Analgesic and antidiarrheal are common to mu, kappa and delta receptors
- respiratory depressant
List some effects of analgesia
- no loss of conciousness
- pain less intense
- drowsiness
- euphoria/mental clouding
- nausea/vomiting
- decreased VA
- apathy/loss of concentration
- continuous dull pain
Which is NOT an effect of analgesia?
A. loss of conciousness B. drowsiness C. euphoria D. decreased VA E. continuous dull pain
A. loss of conciousness
Which is the effect of increasing the dosage of morphine? (Euphoria, Respiration, Incoordination, Mood)
- more euphoria/dysphoria
- decreased respiration
- no incoordination
- mood alteration (via dopamine pathway)
What are the effects of morphine on the pupil?
Miosis/mydriasis?, how is it stimulated, tolerence?, what is an example of an opiate antagonist, effects on IOP
- stiulated ANS oculomtor at EW nucleus
- no tolerance
- atropine is an opiate antagonist
- decrease IOP in normal patient
What are the effects of morphine on respiratory system?
pCO2 levels, pCO2 responsiveness, what receptors are acted on, cough reflex
- severe respiratory depression (toxicity)
- increased PCO2, decreased responsiveness to PCO2
- depression of respiration control
- endorphins act on mu receptors
- decreased cough reflex (anti-tussive)
What are the effects of morphine on cardiovascular system?
blood pressure, intracranial pressure, effects if administered intravenously
- orthostatic hypotension (lower blood pressure)
- increased intracranial pressure (contraindicated in head trauma)
- histamine release (vasodilation) if IV injection
What are the effects of morphine on GI tract?
effect on diarrhea, propulsion in GI, water absorption, digestion, what drug will reverse effects, urination, ADH
- anti-diarrheal
- constipation
- decrease GI propulsion
- increased water absorption, decreased urination and increased ADH release
- slowed digestion
What are the metabolism properties of morphine?
(first pass effect, oral effectiveness, is there glucaronide conjugation and re-circuation, how well does it absorb SC, IM, IV)
- rapid first pass metabolism
- no very effective orally
- glucaronide conjugation, enterohepatic recirculation
- well absorbed SC, IM, IV
Name two specific opiate receptor antagonists and a specific use for them.
- Naltrexone
- Naloxone
- effective in overdose
- give Naltrexone for severe respiratory depression of unknown cause. No response = no opiate overdose
