FB - Opioid Analgesics Flashcards
What is the pharmacodynamic characteristics of codeine?
Weak opioid agonist
Why is early control of pain important?
When pain becomes severe, it is less responsive to treatment
How do opioids inhibit pain signal propagation?
By blocking opioid receptors and inhibiting propagation of pain signals
Name the major types of opioid receptors.
µ (Mu), δ (Delta), κ (Kappa)
What is the role of µ (Mu) receptors in opioid analgesia?
Supraspinal and spinal analgesia, respiratory depression, euphoria
What effects are associated with κ (Kappa) receptors?
Peripheral analgesia, dysphoria, and sedation
How do individual differences affect opioid dosing?
Factors like age and type of pain (neuropathic vs nociceptive) influence dosing requirements
What is the principle of ‘dosing to effect’ in opioid therapy?
Starting with a low dose and titrating until adequate analgesia is achieved or until side effects necessitates termination
What a clinical uses for codeine?
cough suppression
What is a common adverse effect of opioids related to the gastrointestinal system?
Constipation due to reduced GI motility
What are the risks associated with opioid overdose?
Respiratory depression, potential lethality, especially in combination with other CNS depressants
What is the primary use of opioid antagonists like naloxone?
To counteract opioid overdose
Why must opioid antagonists be used cautiously in patients with opiate dependency?
They can precipitate a potentially fatal withdrawal syndrome
How do opioids like morphine affect driving or operating machinery?
They cause drowsiness, requiring caution
What is the impact of long-term opioid use on the immune system?
It may have an immunosuppressant effect
How do opioids potentially affect patients with asthma?
Morphine can trigger histamine release, causing bronchoconstriction
What characterizes opioid tolerance?
Reduced effectiveness over time, requiring dose escalation
Define opioid addiction.
Psychological craving, compulsive use, and loss of control over use
What happens during physical dependence on opioids?
Stopping the drug leads to physical withdrawal symptoms
What are signs of opioid withdrawal?
Anxiety, irritability, chills, nausea, vomiting, abdominal cramps
Why is morphine considered a strong opioid agonist?
High affinity to opioid mu receptors, highanalgesic efficacy and liability for addiction/abuse
What distinguishes methadone and fentanyl among strong opioid agonists?
Methadone is long-acting; Fentanyl is short-acting and thus often used as an anaesthetic adjuvant
What are the characteristics of moderate opioid agonists like codeine?
Weak opioid receptor agonist, low analgesic efficacy, moderate liability for addiction/abuse
How does pethidine (Meperidine) differ from morphine?
Shorter duration of action, produces restlessness rather than sedation
