Analgesics 3: Opioids

Question 1

Opioids

what does the change in functional groups display in heroin and morphine do?

Answer 1

they serve to decrease the time of onset of effect

Question 2

opioids

what awre 4 semi-synthetic opioids

Answer 2

• heroin
• codeine
• oxycodone
• diamorphine

Question 3

opioids

what type of opioid drug is Naloxone

Answer 3

naloxone is an opioid receptor antagonist

Question 4

opioids

what are 4 synthetic opioids

Answer 4

• pehtidine
• fentanyl
• methadone
• buprenorphine

Question 5

opioids

what are the 4 opioid receptors opioids act on

Answer 5

• µ
• δ
• κ
• NOP (ORL1)

Question 6

analgesic action of opioids

via what opioid receptor does analgesic action occur?

Answer 6

occurs through µ opioid receptors

Question 7

analgesic action of opioids

where can µ receptors be found in the body and thus where can opioids provide analgesic action

Answer 7

can be found:

• in periphery
• in spinal column
• supraspinal areas (I.e brain)

Question 8

analgesic action of opioids

what are opioids useful for and what are they not useful for

Answer 8

• acute pain
• “end of life” pain
• not useful for neuropathic or chronic pain

Question 9

analgesic action of opioids

what type of receptors are opioid receptors and what does this lead to

Answer 9

g-protein couple receptors

• specifically coupled to Gi protein
• leads to decreased cAMP and increase in potassium conductance, which leads to decreased neurotransmitter release

Question 10

opioids

what are 4 other uses of opioids other than as analgesics

Answer 10

-sedation
-treatment of diarrhoea
- anti-tussive (stops coughing)
- treament of opioid addictions

Question 11

opioid- potencies

what are the weak opioids?

Answer 11

tramadol
codeine

Question 12

opioids

what are the strong opioids

Answer 12

methadone
buprenorphine
fentanyl

Question 13

opioid- adverse effects

what are 11 unwanted effects of opioids

think: MORPHINE SCT

Answer 13

• Miosis
• Orthostatic hypotension
• Respiratory depression
• Pain suppression/Pruritis
• Histamine release
• increased intracranial tension
• Nausea
• euphoria
• sedation
• constipation
• tolerance

Question 14

opioids- codeine vs morphine

what molecule converts codeine to morphine

Answer 14

the isoform of CYP called CYP-2D6

Question 15

opioids - codeine vs morphine

what are the 2 phases of metabolism that allow codeine to become an active opioid?

Answer 15

Phase 1: metabolism of codeine via CYP3A4 and CYP2D6 (this one mainly)

Phase 2: metabolism of the newly converted morphine via glucuronyl transferase (UGT) to make morphine more water soluble

Question 16

opioids- codeine vs morphine

how are all forms of bioactive converted codeine excreted

Answer 16

renal excretion

Question 17

Opioids - Tramadol

what is the dual action of Tramadol

Answer 17

1. opioid receptor agonist
2. Noradrenaline and 5HT reptake inhibitor

Question 18

Opioids - Tramadol

what is tramadol metabolised by?

Answer 18

• CYP2D6
• CYP2B6
• CYP2A4

Question 19

opioids - Tramadol

where does tramadol act and what is its potent metabolite?

Answer 19

• active at µ receptors
• potent metabolite: O-desmethyl-tramadol

Question 20

Principles of Drug therapy

what are the 7 principles of drug therapy regarding analgesics

Answer 20

1. continous pain requires continuous relief
2. use oral route when possible
3. parenteral route if vomiting or dysphagia occurs
4. dose for each patient should be individually determined
5. reassess pain at each change of analgesia
6. explain each change of mediation and reassure patient
7. follow the analgesic ladder