Opiod Analgesia

Question 0

Define opiods

Answer 0

Opiod receptor agonist

Question 1

Name some opiates

Answer 1

Drugs derived from opium,

Morphine codeine papaverine

Question 2

Morphine

Answer 2

Derived from phenanthrene
Analgesic propetprties
Extensive first pass metabolism

Question 3

Diamorphine

Answer 3

Heroin
Extensive first pass metabolism
More lipid soluble than morphine
Poor affinity for mu receptors

Question 4

Codeine

Answer 4

Weak opiod for mu
50% morphines analgesia
Analgesic effects due to metabolism into morphine

Question 5

Dihydrocodeine

Answer 5

Analgesic properties due to parent molecule or metabolite (dihydromorphine)

Question 6

Tramadol

Answer 6

Atypical opiod
Analogue of codeine
Causes pyschosis due to serotonergic activity

Question 7

Talpentadol

Answer 7

Mu receptor agonist

Question 8

Oxycodone

Answer 8

Mu and kappa
Good bioavailability
Bad side effects

Question 9

Hydromorphone

Answer 9

Ketone of morphine
More potent than mor
Highly water sol
Preferable in renal failure?

Question 10

Methadone

Answer 10

Mu
Raecemic r= more affinity for r
S has additional nmda antagonistic effect and inhibits reuptake of 5ht and norepinephrine
Metabolised in liver, excreted in faeces therfore good for renal failure
Use for opiod addiction and neuropathic pain.

Question 11

Fentanyl

Answer 11

Synthetic opiod agonist
V potent
Highly lipophilic
Metabolised in liver

Question 12

Buprenorphine

Answer 12

Partial agonist, high affinity but low efficacy
Mu receptor
Use in opiod addiction

Question 13

Naloxone

Answer 13

Opiod antagonist
Low oral availability
Rapid onset and short duration of action

Question 14

Naltrexone

Answer 14

Orally active with long duration of action

Used in opiod addiction

Question 15

Methylnaltrexone

Answer 15

Peripherally acting mu receptor antagonist

Used for opiod induced constijpation

Question 16

Adverse effects of opiods

Answer 16

Respiratory depression
Nausea and vomiting
Sedation
Constipation
Hypotension

Question 17

How do opiods work?

Answer 17

Directly bind to mu receptors in dorsal horn in spinal cord.
Opiods activate descending nerve fibres ffrom periaquiductal grey and raphe nuc, these control endogenous opiod containing interneurones, thereofre decreasing ascending pain pathways