The Medicinal Chemistry of Opioid Analgesics 1 Flashcards Preview

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Flashcards in The Medicinal Chemistry of Opioid Analgesics 1 Deck (37)
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1

What are opioid alkaloids?

Centrally acting analgesics
Possess strong narcotic effect in terms of side effects

2

What kind of narcotic side effects can come from opioid use?

Sedation and even loss of consiousness

3

What are the indications of opioids?

Moderate to severe pain analgesia
Cough e.g. codeine, dihydrocodeine, ethylmorphine
Diarrhoea e.g. loperamide
Opioid dependence e.g. methadone and buprenorphine

4

Common adverse reactions to opioids?

Respiratory depression
Nausea and vomiting
Drowsiness
Itching
Dry Mouth
Constipation
Miosis

5

Problems associated with opioids?

Tolerance
Physical Dependence
Addiction

6

Where do delta (δ) opioid receptors exist and what is the agonist function?

CNS (brain) and ENS
Analgesia, antidepressant and physical dependence

7

Where do kappa (k) opioid receptors exist and what is the agonist function?

CNS (brain, spinal cord) and ENS
Spinal analgesia, sedation, miosis, inhibition of ADH release (anti-diuretic hormone)

8

Where do mu (μ) opioid receptors exist and what is the agonist function?

CNS (brain, spinal cord,) and ENS and GI
μ1 Supraspinal (above spine) analgesia
Physical dependence
μ2 Respiratory depression
Miosis and reduced GI motility

9

Agonist action at which opioid receptor causes respiratory depression and constipation?

μ2 opioid receptor

10

Agonist action at which opioid receptor causes anti depressant effects?

δ opioid receptor

11

Where are endorphins isolated from?

Pituitary glands

12

What are the two most important enkephalins?

Leu-Enkephalin
Met-Enkephalin

13

Which amino acid is found at the terminal of leu and met enkephalin?

Tyrosine

14

What is the difference between phenol and alcohol group?

Phenol is more acidic, can ionise more readily and is more polarised, making it a better H bond donor

15

What benefit do the rings in the morphine structure hold?

Rigidity which is good for receptor binding

16

What happens if you change the phenol group on morphine structure 3rd carbon?

All modifications lead to reduced analgesic activity

17

What is produced if you change the -OH phenol group on carbon 3 of morphine to an ether with a CH3 as the functional group?

Codeine

18

What is produced if you change the -OH phenol group on carbon 3 of morphine to an ether with a Et (ethyl) as the functional group?

Ethylmorphine

19

What is produced if you change the -OH phenol group on carbon 3 of morphine to an ether with an Acetyl as the functional group?

3-Acetylmorphine

20

How does codeine act as a prodrug?

Codeine is metabolised in the liver into morphine which then has the analgesic effect

21

What happens in liver metabolism of codeine to produce morphine?

Methyl group is cleaved

22

What is produced if you change the -OH alcohol group on carbon 6 of morphine to a CH3 as the functional group?

Heterocodeine

23

What is produced if you change the -OH alcohol group on carbon 6 of morphine to an Et (ethyl) as the functional group?

6-Ethlymorphine

24

What is produced if you change the -OH alcohol group on carbon 6 of morphine to a Acetyl as the functional group?

6-Acetlymorphine

25

What happens to the analgesic activity of moprhine when the phenol at carbon 3 is modified?

Reduced analgesic activity

26

What happens to the analgesic activity of morphine when the -OH alcohol group at carbon 6 is modified?

4-5 fold increase in activity

27

What is the nomenclature of diamorphine / heroin?

3,6 - diacetylmorphine
The phenol group and -OH group at carbon 3 and 6 are replaced by acetyl groups

28

What is the ultimate resistance to CNS receptor access?

Blood Brain Barrier

29

What kind of molecules enter the CNS across the BBB easily?

Highly lipophillic

30

Examples of lipophillic opioid drugs that can cross the BBB?

6-acetylmorphine and heroin (3,6, diacetylmorphine)