PRELIMS: Opioid Flashcards
What are the two main categories of analgesic drugs?
Opioid Analgesics
Non-opioid Analgesics
Which opioid receptor is most associated with the analgesic effects of many opioids?
Mu receptors
Name a prototypical opioid analgesic.
Morphine
What are the three primary classes of opioid receptors?
Mu
Kappa
Delta
List two examples of strong opioid agonists.
Fentanyl
Morphine
Name a concern associated with the stimulation of mu receptors.
Respiratory depression and constipation
What are mixed agonist-antagonists and provide an example?
Definition: Drugs that exhibit both agonist and antagonist activity at different opioid receptors.
Example: Buprenorphine
What are endogenous opioid peptides?
Endorphins
Enkephalins
Dynorphins
What is the function of opioid antagonists like Naloxone and Naltrexone?
Naloxone: Rapidly reverses opioid-induced respiratory depression.
Naltrexone: Used to maintain an opioid-free state and treat alcohol dependence.
How do transdermal patches benefit opioid administration?
Provide steady, prolonged administration.
Avoid GI tract, reducing problems like constipation.
What is the primary site of opioid metabolism?
Liver
What are the primary routes of administration for opioids?
Oral
Suppository
Parenteral (Subcutaneous, Intramuscular, IV)
Transdermal
Iontophoresis
Transmucosal and Intranasal
What are the benefits of opioid analgesics in rehabilitation?
Reduce pain
Help patients be more active and engaged in exercise and rehabilitation
Describe the spinal effects of opioids.
Location: Dorsal horn of the spinal cord
Action: Inhibit synapses transmitting nociceptive input
Presynaptic Effects: Decrease release of pain-mediating transmitters
Postsynaptic Effects: Hyperpolarize the postsynaptic neuron
List some issues associated with opioid use.
Sedative properties
Mood changes
Cardiovascular effects (orthostatic hypotension)
Gastrointestinal distress (nausea, vomiting, constipation)
What are the effects of opioids on peripheral sensory nerve endings?
Decrease excitability
Mechanism: Likely involves inhibition of adenyl cyclase activity and control of ion channels
Name two common side effects of opioids.
Respiratory Depression
Constipation
Where do opioids act in the brain, and what is their effect?
Location: Brain regions associated with pain transmission (e.g., Periaqueductal gray matter)
Effect: Activate descending pain pathways, leading to inhibition of pain transmission at the spinal cord
What is tolerance, and what are its physiological mechanisms?
Definition: Need to increase drug dosage to maintain therapeutic effects over time.
Mechanisms:
Receptor Downregulation and Desensitization
Receptor Recycling
G Protein Disruption
Increased Pain Pathways
Describe the onset and duration of tolerance.
Onset: Begins after the first dose
Noticeable: After 2-3 weeks
Duration: Lasts 1-2 weeks after drug removal
What is physical dependence, and how does it differ from addiction?
Definition: Onset of withdrawal symptoms when the drug is abruptly stopped.
Symptoms: Peak 2-3 days after last dose, lasting around 5 days.
Distinction: Different from addiction which involves cravings and drug-seeking behavior.
How does Patient-Controlled Analgesia (PCA) benefit patients?
Allows patients to control their own analgesic delivery
Commonly used post-surgery, for chronic pain, and cancer-related pain
What are the effects of opioids on gastrointestinal motility?
Decrease GI motility
Used to control severe diarrhea
Can cause severe constipation
Define addiction in the context of substance use.
Repeatedly ingesting substances for mood-altering and pleasurable effects, such as seeking an opioid “high.”