D3 Opiates

Question 1

essential idea of opiates

Answer 1

potent med drugs prepped by chem modification of natural products
- can become addictive and substances of abuse

Question 2

what are opiates

Answer 2

natural narcotic analgesics derived from the opium poppy

Question 3

how do opitates prevent pain

Answer 3

preventing the transmission of pain impulses in the brain rather than at the source

Question 4

where do analgesic properties of opitates come from

Answer 4

• humans possess opioid receptors in brain – temporary binding blocks transmission of impulses betw brain and pain signalling cells
• interferes with perception of pain w/o depression central nervous system

Question 5

what are the effects of opiates

Answer 5

act on brain = change in behaviour and mood = a narcotic
- effective painkillers, but addictive properties + side effects

Question 6

what is the blood brain barrier

Answer 6

a membrane that surrounds the brain to protect it
- hydrophobic, non-polar environment (not easily crossed by polar molecules)

Question 7

what does the ability of the drug to cross blood brain barrier depend on

Answer 7

chemical structure and solubility in water and lipids

Question 8

what solubility types are impt in where 2

Answer 8

chem structure determines solubility!
- aqueous solubility impt in blood
- lipid solubility impt in crossing blood brain barrier

Question 9

side effects of using strong analgesics 4 (disadvantages)

Answer 9

• constipation
• suppresson of cough reflex
• contriction of pupil (Eye)
• narcotic effects (eg slowed breathing, nausea, drowsiness)

Question 10

pain management: WHO 3 step analgesic ladder

Answer 10

1. use mild analgesics
2. add weak opioid eg codeine/tramadol
3. severe pain: strong opioids eg morphine, methadone

Question 11

synthesis of codeine

Answer 11

syn. from morphine thru methylation reaction
- one hydroxyl grp is methylated to prod. codeine

Question 12

synthesis of diamorphine (heroin)

Answer 12

syn, from morphine thru acetylation reaction
- two hydroxyl grp acetylated

Question 13

codeine vs diamorphine

Answer 13

synthesis: methylated vs acetylated
change 1 OH grp vs 2
- both from morphine
- both change hydroxyl (-OH) groups

Question 14

why is diamorphine more potent than morphine 3

Answer 14

• increased lipophilicity from additional acetyl grps
• dia.m crosses blood brain barrier more rapidly = enhanced central nervous sytem effects, incr potency
• dia.m undergoes rapid hydrolysis in body into morphine (active metabolite) = incr potency

Question 15

what derivative of morphine is most potent and why

Answer 15

6-acetylmorphine
- contains ester link at only one position
- does not need to undergo hydrolysis reaction (before interacting w brain cells)
- prod as a metabolite from heroin in body BUT
- high activity = extremely dangerous in pure form

Question 16

morphine structure and functionla grps

Answer 16

the 2 -OH on top and bottom right

• arene
• ester
• alkenyl
• hydroxyl (2)
• tertiary amino (constant)

Question 17

codeine structure and functional grps

Answer 17

-OH at top right,
- O - CH3 on bottom right

• arene
• ester 2
• alkenyl
• hydroxyl (1)
• tertiary amino (constant)

Question 18

diamorphine structure and functional groups

Answer 18

-O-C = O
– CH3
on both top and bottom right

• arene
• ester
• alkenyl
• ester (ethanoate) 2
• tertiary amino (constant)

Question 19

where is codeine obtained from

Answer 19

0.5% raw opium
usually prepped from morphine

Question 20

where is morphine obtained from

Answer 20

raw opium 10%

Question 21

where is diamorphine obtained from

Answer 21

found in opium BUT usually obtained thru reaction of morphine

Question 22

theraputic uses of codeine

Answer 22

• sometimes used in prep with non-narcotic drugs (eg paracetamol/aspirin) in 2nd stage of pain management ladder
• used in cough meds + short term diarrhoea treatment

Question 23

theraputic uses of morphine

Answer 23

• managemnt of severe pain eg advanced cancer
• can lead to dependence – must be regulated by a medical professional

Question 24

theraputic uses of diamorphine

Answer 24

• medically used only in a few countries legally
• most rapidly acting, most abused
• initial euphoric effects, but high potetial for addiction and incr tolerance
• dependence –> withdrawl symptoms