Opioid Analgesics 2 Flashcards
(36 cards)
What opioid receptor will give you spinal analgesia, miosis (pinpoint pupils) and sedation?
Kappa
What opioid receptors give you analgesia, emotion and seizures?
Delta
What opioid receptors give you dyphoria, hallucinations, nightmares, anxiety?
Sigma
What opioid receptor gives you just analgesia?
Epsilon
The strength of attachment of an opioid drug to its binding site is proportional to what?
It’s potency
The stronger the affinity - the higher the potency
Opioids act by?
- Presynaptic inhibition of production of neurotransmitters C-fiber endings
- Postsynaptic suppression of evoked activity in nociceptive path or remove the remaining parts of the regulation of inhibition of nociceptive impulses
- Increased transmission of the descending inhibition of spinal nociceptive conduction
What do opioids cause (3 things)?
- Hyperpolarization of nerve cells
- Inhibition of nerve firing
- Presynaptic inhibition of transmitter release
What are the examples of opioids?
- Endogenous opioid peptides
- Opium alkaloids (poppy plants - morphine and codeine)
- Semi-synthetic opioids
- Fully synthetic opioids
What’s a pure agonist, and what is the prime example of a pure agonist?
Complete receptor activation - mu and kappa activated
Unlimited analgesia - MORPHINE
What’s a major problem with opioids?
Tolerance - the potency of the drug declines so that progessively higher concentrations are required to produce the same degree of analgesia -
What are the characteristics of a partial agonist and give an example?
Example: buprenorphine (Buprenex)
Parital mu activation, good analgesia but limited effect
If one become tolerant to one opioid what is a possibility with other opioids?
They can become cross-tolerant to other opioids
What is an example of agonist/antagonist?
Example: pentazocine (Talwin)
- Mu - anatagonist
- Kappa - agonist (sedative prior to sugery, supplement to surgical anesthesia)
What is an example of a pure antagonist, and what are the characteristics?
Example: naloxone (Narcan)
No analgesia
What is used for an antidote of overdosed opioids?
naloxone (Narcan)
Pure antagonist - used for complete or partial reversal of opioid depression
Where are opioids absorbed?
Most are well-absorbed orally
Lungs, nasal and oral mucosa, and intact skin all good places as well
What’s the distribution of opioids?
First pass effect reduces bioavailability, can pass to fetus
***What are the desired clinical effects of opioid drugs?
- Potent analgesia
- Sedation and euphoria
- Cough suppression
-
GI effects
- increase smooth muscle tone
- decrease propulsion and motility
- used for treatment of diarrhea
What’s the number one compliant of people who take opiates?
Constipation
All opiates have the same adverse reactions, what are the?
- Physical addiction
- Respiratory depression
- Nausea and vomiting
- Constipation
- Miosis (pinpoint pupils)
- Urinary retention
- CNS effects - stimulatory effects, anxious
- Cardiovascular - bradycardia (depressent)
- Biliary tract constriction
- Histamine release - itching and urticaria
Why don’t we use opioids in pregnancy?
Prolongs labor, depresses fetal respiration if given near term, infants born addicted
The severity of the side effects of opiates are proportional to its _________?
Efficacy
What are signs of opioid overdose?
- Respiratory depression
- Pinpoint pupils
- Coma
Treat with anatagonist - naloxone
What are signs of opioid withdrawal?
- Yawning, lacrimatoin, perspiration, piloerection, irritability, tachycardia, tremors, etc
