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.”
How can opioids positively and negatively affect rehabilitation patients?
Positive Effects: Pain relief, facilitating more vigorous rehabilitation, scheduling therapy sessions when opioids are most effective.
Negative Effects: Sedation, GI discomfort, respiratory depression, constipation.
Define psychological dependence.
Motivation to use drugs to reproduce pleasurable sensations, leading to continued drug-seeking behavior.
List some key drugs classified as NSAIDs.
Aspirin
Acetaminophen
Other NSAIDs (understanding their mechanisms and effects is crucial for patient management)
Describe the key pharmacological properties of NSAIDs.
Anti-inflammatory: Decreases inflammation
Analgesic: Relieves mild-to-moderate pain
Antipyretic: Reduces fever
Anticoagulant: Inhibits platelet aggregation
What is the historical context of aspirin in relation to NSAIDs?
Aspirin is considered the prototype NSAID and is often used as a benchmark for comparing the efficacy and safety of newer NSAIDs.
What are opioid-induced hyperalgesia and its potential causes?
Definition: Increased pain sensitivity or lack of response to opioids.
Causes: Genetic predispositions, increased glutamate activity, increased sensitivity of NMDA receptors.
What are common pharmacological treatments for opioid addiction?
Methadone: Substitutes for abused opioids; reduces withdrawal symptoms.
Buprenorphine: Mixed agonist-antagonist; reduces abuse potential when combined with Naloxone.
Describe the mechanism of action for aspirin and other NSAIDs.
Aspirin and other NSAIDs interfere with the biosynthesis of prostaglandins, which are involved in pain, inflammation, fever, and blood clotting.
What was discovered in the early 1970s regarding NSAIDs?
Researchers discovered that the therapeutic effects of aspirin and NSAIDs are linked to their impact on prostaglandin biosynthesis.
What role do leukotrienes play, and which drugs target them?
Leukotrienes are pro-inflammatory and important in airway inflammation (e.g., asthma, allergic rhinitis).
Drugs:
LOX Inhibitors: Zileuton
Leukotriene Receptor Blockers: Montelukast, Zafirlukast
How are eicosanoids, including prostaglandins, thromboxanes, and leukotrienes, biosynthesized?
: Eicosanoids are derived from arachidonic acid, which is cleaved from cell membranes by phospholipase A2.
COX Enzymes: Produce prostaglandins and thromboxanes.
LOX Enzymes: Produce leukotrienes
What are prostaglandins, and where are they produced?
Prostaglandins are lipid-like compounds with diverse physiological activities, produced by almost all cells except red blood cells.
What is the significance of NSAIDs in physical rehabilitation?
Frequently used to manage pain and inflammation, with therapy tailored to each patient’s needs.
How do prostaglandins and thromboxanes influence various physiological systems?
Vasodilation vs. Vasoconstriction: Some prostaglandins cause vasodilation; others and thromboxanes cause vasoconstriction.
Effects on Systems: Influence cardiovascular, respiratory, renal, gastrointestinal, nervous, and reproductive systems.
How does acetaminophen differ from NSAIDs like aspirin?
Acetaminophen decreases pain and fever but lacks anti-inflammatory and anticoagulant properties, so it is not classified as an NSAID.
How does the inhibition of thromboxane synthesis affect clotting?
Inhibition of thromboxane synthesis helps prevent excessive clotting by reducing platelet aggregation and clot formation.
What are some pathological conditions associated with prostaglandins and thromboxanes?
Inflammation: Prostaglandins mediate erythema, edema, and increase blood flow and capillary permeability.
Pain: Prostaglandins increase the sensitivity of pain receptors.
Fever: Prostaglandins alter the thermoregulatory set-point in the hypothalamus.
Dysmenorrhea: Increased prostaglandin production in the endometrium causes menstrual cramps.
Thrombus Formation: Thromboxanes cause platelet aggregation and clot formation.
