Opioids Flashcards
What are endorphins?
Polypeptides that come from poropiomelanocortin and prodynorphin in the pituitary and hypothalamus that are potent analgesics
What do endorphins work?
Hyperpolarization of nerves by opening K and Ca channels in 1st and 2nd order neurons
Inhibition of ascending pathways in the CNS
Excitation of descending adrenergic and seratonerigic pathways
What is the mu receptor?
An opioid receptor that modulates most of the effects of opioids
What would happen if you got rid of the mu receptor?
You would be more sensitive to pain and less responsive to morphine
What group of people are less responsive to opioids?
Red heads
Which opioids are phenanthrene derivatives?
Morphine, codeine, hydrocodone, hydromorphone, oxycodone
Which opioids are phenylpiperidine derivatives?
Meperidine, fentanyl, sudenatil
Which opioid is a diphenylheptane derivative?
Methadone
What opioids are naturally derived from poppy seeds?
Morphine and codeine
What was the first semi synthetic opioid?
Diacetyl morphine (heroin) gets into brain faster than regular morphine
What are the pharmacological effects of opioids?
Inhibition of pain and pain perception, sedation and anxiolysis (drowsiness, cognitive impairment), depression of respiration, cough suppression, reduction of intestinal motility, pupil constriction, nausea and vomiting (stimulates then inhibits)e
When would depression of respiration from opioids be clinically useful?
People with respiratory failure who are close to dying and gasping for air
Scuba divers use to make oxygen tanks last longer (stupid)
What is the main cause of death from opioid overdose?
Depression of respiration
What is the saying for opioids?
By the mouth by the clock by the ladder
Why are opioids usually given by mouth?
Less effective than IV but has longer effect requiring less doses
Avoids the “highs” and is thus less addictive
Safer in terms of overdose
What does it mean to give opioid ‘by the clock’?
Give the opioid based on time rather than pain so there won’t be a time between where you’re in pain and have to get out of it
What are the benefits of giving opioids ‘by the clock’?
Uses less drug to maintain rather bring out of pain
Avoids euphoria associated with release of pain
Avoids development of chronic pain syndromes from pathway rewiring
How does dosing opioids ‘by the ladder’ work?
Assures the safest and least potent drug is used
Avoids addictive potential because opioids are not used until required
What is the WHO Pain Ladder?
Mild: NSAIDs
Moderate: NSAIDs + codeine
Severe: Morphine + NSAIDS + codeine
What is codeine?
The weakest, most commonly used opioid (little addiction risk) with 10% the potency of morphine
What is codeine used for?
Pain, diarrhea, coughing and to inhibit breathing
What drugs shares a step in the pain ladder with codeine?
Tramadol
What makes tramadol unique from other opioid agonists?
Has 2 complementary mechanisms:
Activates mu opioid receptor (like other opioids)
Weak inhibitor of norepinephrine and serotonin reuptake
Less potential for addiction, greater pain control (better against joint pain)
What are the pharmacokinetics of morphine?
Oral: Poor availability 15-60 minutes before onset Lasts 3-6 hours IV: Twice as potent as oral Duration can either be immediate or about 2 hours
