Opioids Flashcards
Final Exam
Analgesics
Analgesics are drugs that relieve pain without causing loss of consciousness.
opioid
An opioid is any drug, natural or synthetic, that has actions similar to those of morphine.
opiate
The term opiate is more specific and applies only to compounds present in opium (e.g., morphine, codeine).
There are three main classes of opioid receptors
- mu,
- kappa
- delta.
What are the most important receptors from a pharmacologic perspective?
Mu receptors
Why are Mu receptors the most important?
are the most important because opioid analgesics act primarily by activating mu receptors (although they also produce weak activation of kappa receptors).
Responses to Mu receptor activation include:
analgesia,
respiratory depression,
euphoria,
sedation
Physical dependence
What is Mu receptors related to?
Physical dependence
Activation of Kappa receptors causes what?
activation of kappa receptors can produce analgesia and sedation.
kappa activation may underlie psychotomimetic effects seen with certain opioids.
Kappa activation may underlie what?
kappa activation may underlie psychotomimetic effects seen with certain opioids.
At each receptor, a drug can act in three ways:
- Agonist
- Partial agonist
- Antagonist
Partial agonist
A drug that produces low to moderate receptor activation when administered alone but will block the actions of a full agonist if the two are given together.
What happens if a partial agonist is given with an agonist?
Partial agonists will block the actions of a full agonist if the two are given together.
Drugs that bind opioids receptors fall into three major categories:
- pure opioid agonists
- agonist-antagonist opioids
- pure opioid antagonists.
What do pure opioid receptors activate?
The pure opioid agonists activate mu receptors and kappa receptors.
By activating mu and kappa receptors, what do pure agonist produce?
The pure agonists can produce analgesia, euphoria, sedation, respiratory depression, physical dependence, constipation, and other effects.
What are the two groups that pure opioid agonists can be subdivided into:
- moderate to strong opioid agonists
- strong opioid agonist
What is the prototype drug for strong opioid agonists
Morphine
Four agonist-antagonist opioids are available: and what is the prototype?
- pentazocine
- nalbuphine
- butorphanol
- buprenorphine
When administered alone, what do agonist-antagonists do?
When administered alone, the agonist-antagonist opioids produce analgesia.
What happens if Agonist Antagonist is given to a patient taking a pure opioid agonist?
Giving an agonist antagonist will block Mu receptors and will stimulate withdrawal symptoms because we block mu receptors that have grown tolerant to the drug.
If given to a patient who is taking a pure opioid agonist, however, these drugs can antagonize analgesia caused by the pure agonist.
What do pure opioid antagonists do?
The pure opioid antagonists act as antagonists at mu and kappa receptors.
What kind of effect do pure opioid antagonists have?
These drugs do not produce analgesia or any of the other effects caused by opioid agonists.
The principal use of pure opioid antagonists?
Their principal use is reversal of respiratory and CNS depression caused by overdose with opioid agonists.
What drug is used to treat opioid induced constipation? What class is it?
methylnaltrexone—is used to treat opioid-induced constipation.
It is a pure opioid antagonist
What is the prototype of the pure opioid antagonists?
Naloxone
What is the prototype drug of the strong opioid analgesics?
Morphine
Pharmacological effects of morphine?
including analgesia
sedation
euphoria
respiratory depression
cough suppression
suppression of bowel motility
Overview of Pharmacologic Actions of Morphine:
relieving pain,
the drug causes drowsiness and mental clouding, reduces anxiety,
and creates a sense of well-being.
Through actions in the CNS and periphery, morphine can cause respiratory depression, constipation, urinary retention, orthostatic hypotension, emesis, miosis, cough suppression, and biliary colic.
Through actions in the CNS and periphery, morphine can cause:
morphine can cause:
respiratory depression,
constipation,
urinary retention,
orthostatic hypotension,
emesis,
miosis,
cough suppression,
and biliary colic.
With prolonged use of morphine, what does the drug produce?
With prolonged use, the drug produces tolerance and physical dependence.
What is the principle indication for morphine?
The principal indication for morphine is relief of moderate to severe pain. `
What type of pain is morphine best for?
The drug is more effective against dull, constant pain than against sharp, intermittent pain.
What is the most serious adverse effect of morphine?
Respiratory depression is the most serious adverse effect.
Time course of respiratory depression with morphine use varies with what?
route of administration.
How long does depressant effects of morphine occur with IV injection?
Depressant effects begin about 7minutes after IV injection
How long does depressant effects of morphine occur with IM injection?
30minutes after intramuscular (IM) injection,
How long does depressant effects of morphine occur with SubQ injection?
up to 90minutes after subcutaneous (subQ)