Opiate Drugs Flashcards
0
Q
Transcutaneous Electrical Nerve Stimulation
A
- TENS
- Electrical stimulation over sensory neurons
- Sensory activtion enhances descending pain control pathways
- Both opioid (enkephalins, dynorphin) & non-opoid (5HT, NE) affected
- Pain controlled at & below the level of stimulation
- Pain relief extends beyond duration of stimulation
1
Q
Endogenous Opiod Peptides
A
- methionine-enkephalin, leucine-enkephalin
- synthesized by pro-enkephalin gene
- dynorphins, synthesized by pro-dynorphin gene
- β-endorphin, co-synthesized with ACTH
- α-MSH in pro-opiomelanocortin
2
Q
Acupuncture
A
- Electrical or mechanical stimulation of needles
- Needles placed in sites selected for specific pain
- Mechanism similar to TENS
- Relief beyond duration of stimulation
- analgesia antagonized by opiate antagonists
3
Q
PAG electrical stimulation
A
- Experimental
- stimulation of electrodes in PAG
- Activate descending pain control pathways
- Antagonized by opoid antagonist
- Release of enkephalins, ß-endorphin into CSF occurs
4
Q
Morphine Absorption
A
- Subcutaneous, IM, and GI
- Significant 1st pass effect
- Not absorbed from stomach b/t weak base gets ionized
5
Q
Morphine Distribution
A
- Partly bound to proteins
- Distributed to all tissues
- Concentrated in parenchymal organs (liver, kidney, lungs, spleen)
- Small portion goes to brain
6
Q
Morphine metabolism
A
- Mainly in liver
- Glucuronic acid conjugation is major route
- morphine-6-glucuronide: active metabolite w/ CNS effects
- N-demethylation to normorphine
- Less active metabolite b/c poor CNS penetration
- Codine gets partially metabolized TO morphine
- depends on CYP2D6 (not analgesic w/ deficient CYP2D6)
7
Q
Morphine Excretion
A
- Polar metabolites go out in urine
- Free morphine & metabolites excreted in feces via bile
8
Q
Opioid Receptors
A
- Mu receptor: all currently used opiate drugs act on this
- analgesia, anesthesia, sedation, miosis, euphoria, constipation
- Respiratory depression
- Kappa receptor: analgesia, miosis, sedation
- Dysphoria
- Delta receptor: may influence affective behavior
- Regulation of CV system
9
Q
Codine
A
- Antitussive: cough suppressant
- Elevates cough tolerance
- 3 methyl-morphine
- Partially metabolized to morphine
- Requires CYP2D6
- weaker than morphine
- Oral administration
- Duration: 3-4h
10
Q
Naloxone
A
- Opioid Antagonist
- Morphine derivative w/ larger N-position substituent
- High affinity for opioid receptor but no opiate effect
- Treat acute opiate overdose
- reverses respiratory depression
- Must be injected b/c completely inactivated by liver
- Short duration: often multiple doses needed to treat OD
11
Q
Naltrexone
A
- Opioid Antagonist
- Morphine derivative w/ larger N-position substituent
- High affinity for opioid receptor but no opiate effect
- Treat acute opiate overdose
- reverses respiratory depression
- Orally active
- Longer acting
- Used in treating opiate addiction & alcoholism
12
Q
Morphine Side Effects
A
- Drowsiness
- Nausea
- Vomiting
- Respiratory distress
- Constipation
13
Q
Dextromethorphan
A
- Antitussive
- Acts centrally to suppress cough
- dextroisomer of active opiate drug
- Has little to no effect on opiate receptors
- NMDA receptor antagonist
- OTC
14
Q
Heroin
A
- Diacetylmorphine
- Enters CNS more rapidly than morphine
- Metabolized to morphine in the liver
- Effects similar to morphine
