Opiods/Pain Flashcards
What receptor do opioids primarily act on?
Mu opioid receptor
What are the three known opioid receptors?
Mu, kappa, delta
How do opioids work generally?
They bind opioid receptors and inhibit ionic currents of nerve fibers in the CNS responsible for transmitting nociception and also indirectly activate the descending inhibitory system in the periaqueductal grey by inhibiting inhibitors of the periaqueductal grey.
How do opioid antagonists work?
They reversibly bind to opioid receptors without agonist activity, which prevents actions of exogenous and endogenous opioids (no clinical effect without opioid agonists)
How do agonist-antagonist opioids work?
Agonist actions on kappa receptors, antagonist actions on mu receptors
How do partial opioid agonists work?
They act as agonists on mu opioid receptors but cannot fully activate the receptor
What are the dose-dependent effects of opioids?
Analgesia, sedation/euphoria, respiratory depression, nausea, constipation, pruritis, and miosis.
Which opioid has the most histamine release?
Morphine
Which opioid has many notable active metabolites that can become problematic in renal failure?
Morphine
Which opioid is largely banned due to a toxic metabolite that can accumulate in renal failure and cause seizures?
Meperidine
Which opioid is a prodrug that does not convert to an active drug in some patients with genetic variants?
Codeine
Which opioid is commonly used for acute pain but does not often lead to histamine release or have many active metabolites?
Dilaudid
What is the active substance in drugs like oxycodone?
Oxycontin
Which opioid has a long half-life, lack of active metabolites, but can cause long QT syndrome at high doses?
Methadone
Which potentially fatal side effect is associated with methadone?
Methadone
What are commonly used agonist/antagonist drugs?
Butorphanol, nalbuphine
What is buprenorphine?
The only clinically available partial agonist available in the united states
What is naloxone?
A opioid antagonist
What does the term opiate refer to?
Drugs derived directly from opium
What does opioids refer to?
All opiate receptor agonists
What two drugs are considered weak opioids?
Codeine and propoxyphene
What are the two alkaloid types of opium?
Phenanthrene series and benzylisoquinoline series
How do opioid receptors work?
They work via G proteins to inhibit cellular adenylyl cyclase activity, activate potassium currents, and suppress calcium currents mostly in the pain transmitting fibers of the CNS
Why is their interpersonal variation in opioid response?
Splice variants in the three opioid receptors