Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Y2 LCRS Pharm HR > Opiates > Flashcards

Opiates Flashcards

1
Q

Around what % of codeine is converted to morphine?

A

5-10%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are mu opioid receptors important for?

A

Nociception

Sensorimotor function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the chemical names for heroin and codeine?

A 
Heroin = diacetylmorphine
Codeine = Methyl morphine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where are mu opioid receptors located?

A

Cerebellum, caudate, NA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which of the synthetic opiates has the highest lipophilicity?

A

Fentanyl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the most potent active metabolite of morphine?

A

Morphine-6-glucuronide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Recall 2 synthetic opiate drugs

A

Methadone

Fentanyl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is naxolone?

A

Antagonist of opioid receptors - due to extended side chain on tertiary nitrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Recall the 3 types of opioid receptor and the types of opioid that act on them?

A

Mu - endorphins
Delta - Enkephalins
Kappa - Dynorphins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Recall 5 side effects of opiate use

A
  1. Depression of respiration (medulla)
  2. Stimulation of CTZ
  3. Miosis
  4. GI effects
  5. Urticaria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the most significant between synthetic opiates and natural opiates?

A

Synthetic drugs have a much higher lipophilicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What chemical group determines the efficacy of an opiate drug?

A

OH groups bound to nitrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Recall the sites of conversion to morphine of heroin and codeine

A

Heroin - brain (can cross the BBB)

Codeine - outside brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Recall 3 mechanisms by which endogenous opioids have a depressive effect on cells

A
  1. Increase K+ efflux to cause hyperpolarisation
  2. Decrease Ca++ efflux
  3. Decrease AC activity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the structure activity relationship of opiate action

A

Tertiary nitrogen permits receptor anchoring

Extension of side chain changes the drug from an agonist to an antagonist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Compare the lipophilicity of heroin, methadone and fentanyl to morphine and explain the consequences of this

A

Number of times more soluble = number of times more potent
Heroin = 2 x
Methadone = 4 x
Fentanyl = 100 x

17
Q

Describe the metabolism and clearance of fentanyl

A

Quickly metabolised and cleared - therefore fast effect but quickly lost

18
Q

How do opiates lead to miosis?

A

Switch on PNS

GABA disinhibited in EW nucleus

19
Q

How do opiates interact with the CTZ?

A

Inhibit GABA leading to DISINHIBITION

20
Q

Why do opiates affect the GIT?

A

Several opioid receptors on myenteric neurons

21
Q

What is the main mechanism driving opiate tolerance?

A

Receptor endocytosis driven by arrestin

22
Q

Describe 2 ways in which opioids affect the cough centre

A
  1. Between cough receptors and medulla (cough centre) are C fibre receptors - these are inhibited by opioids
  2. Receptors in cough centre = 5HT1A which are negative feedback receptors for serotonin (which inhibits cough) - opiates inhibit 5HT1A receptors so more serotonin in cough centre
23
Q

Recall 3 useful effects of opioid drugs

A
  1. Analgesia
  2. Euphoria
  3. Anti-tussive
24
Q

Compare the effects of morphine and Morphine-6-glucuronide

A

Morphine is more likely to cause adverse side effects

25
Q

Why does methadone act as an effective morphine replacement?

A

Persists in the body for a long time due to accumulation in fat so effect more sustained

26
Q

Explain the rebound effect of cells in opiate withdrawal

A

Depressant drugs decrease cellular activity
Cells increase AC in response
When you remove opiate - overactive AC
–> muscle cramping and diarrhoea

27
Q

What is the effect of opiates on the GIT?

A

Severe constipation

28
Q

How can heroin have efficacy if it doesn’t have any OH groups bound to the tertiary nitrogen?

A

It is converted to morphine within the brain

29
Q

Describe the metabolism and clearance of methadone

A

Much slower than fentanyl as many more enzymes involved

Likely to accumulate in fat due to slow clearance and high lipophilicity

30
Q

How does heroin’s structure differ from that of morphine?

A

Replace the 2 OH groups on the tertiary nitrogen with acetyl groups

31
Q

What is the pKa of opiate drugs, and what does this indicate about site of absorption?

A

8

Small intestine

32
Q

Which enzyme is responsible for the conversion of codeine to morphine?

A

CYP2D6

33
Q

Recall the 2 mechanisms by which a respiratory rhythm is generated and how opiates interact with these

A
  1. Central chemoreceptors give tonic drive to resp centre
  2. Pre-botzinger complex generates rhythm
    Both inhibited by opiates
34
Q

How can opiates result in urticaria?

A

Bond to receptors on mast cells to stimulate histamine release

35
Q

What treatment is given in opiate overdose?

A

Naxolone

36
Q

How does opiate overdose affect blood pressure?

A

Hypotensive crisis

Due to excessive histamine release

37
Q

How does the pKa of opiates affect their bioavailability

A

Blood pH = 7.4. pKa = 8, therefore only about 20% of drug is unionised (bioavailable)

38
Q

Compare the enzymes that metabolise fentanyl and methadone

A 
Fentanyl = just CYP450 3A4
Methadone = 6 or 7 different enzymes

Y2 LCRS Pharm HR (31 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions