Week 4 - Opioids

Question 1

How old is morphine?

Answer 1

• First reported in 2100 BC.
• Continually reported from thereafter
• 1804 Morphine isolated by German Freidrich Serturner.
• Then distributed in 1817 under Serturner&Company for the first time.

Question 2

How opioids work in the body

Answer 2

• Mu, Kappa and Delta receptors found predominately in the brain stem, Limbic system and Cortex
• Mu receptor
  
  • supraspinal analgesia
  • euphoria
  • respiratory depression
  • ## physical dependence

Question 3

Adverse effects

Answer 3

• Potentially fatal respiratory depression
• Nausea, Vomiting and constipation
• Hallucinations and confusion

Question 4

Examples of strong opioids

Answer 4

• Morphine (Gold standard)
• Heroin
• Methadone

Question 5

Addiction and the consequences

Answer 5

• Addiction is the changes in behavior when one becomes physically dependent on a substance, often for non-medical reasons e.g. mood altering effects rather than pain relief
• around 1905 there was an opioidphobia based on concerns about addiction and dependence
• Huge spike in oxycodone use as well as disproportionate death rate due to oxycodone.
• Long term opioid treatment of non cancer patients actually fulfills none of the desired outcomes (pain relief, improved quality of life and improved functional capacity).

Question 6

Anesthesia and potency

Answer 6

• The higher the oil-gas partition coefficient, the higher the potency
• The lower the blood-gas partition coefficient, the faster the onset and recovery time of the anesthesia.
• The unit MAC (minimum alveolar concentration;
  1 MAC = dose at which 50% of subjects do not react
  to skin incision)

Question 7

Examples

Answer 7

• Thiopental (1934)
  
  • fast onset and recovery
  • unstable solution, repeated doses dangerous and
    respiratory/cardiovascular depression.
• Propofol (1977)
  
  • Most commonly used today
  • fast onset, fast metabolism, ideal for general ana
  • painful injection , cardiovascular/respiratory
    depression
• Ketamine (1942)
  
  • NMDA receptor antagonist
  • Dissociative anaesthesia (only moderate hypnosis)
  • fast onset, low cardiovascular/respiratory depression
    making it ideal for the field
  • hallucinations and nightmares