08.2 Analgesia

Question 1

What are some endogenous opioids?

Answer 1

Endorphins
Enkephalins
Dynorphins

Question 2

What are the classes of exogenous opioids?

Answer 2

Natural
Semi synthetic
Synthetics

Question 3

What are some names of opioid analgesics to be aware of?

Answer 3

Morphine
Diamorphine
Codeine
Tramadol

Question 4

What receptors can opioids act upon?

Answer 4

Mu - most act on this
Kappa
Delta

Question 5

What happens after opioids bind to an opioid receptor?

Answer 5

Activates Gi
Decrease cAMP
Decreased Calcium levels
Decreased neurotransmitter release

Question 6

What is a full antagonist of opioid receptors?

Answer 6

Naloxone

Question 7

What is the use of Naloxone?

Answer 7

Reverse opioid ADRs, namely, respiratory depression

Question 8

Why do you need to give multiple doses of Naloxone over time?

Answer 8

Naloxone has a shorter half life than morphine

Question 9

What is the oral bioavailability of morphine like?

Answer 9

25%

Question 10

What is the oral bioavailability of methadone?

Answer 10

90%

Question 11

What is the oral bioavailability of codeine?

Answer 11

50%

Question 12

What is unique about Codeine’s metabolism?

Answer 12

Prodrug, activated into morphine by CYP2D6

CYP2D6 has genetic polymorphism and hence lots of Chinese people and 10% of caucasians cannot convert it effectively

Question 13

What are some ADRs for opioids?

Answer 13

Respiratory depression
Euphoria
Confusion
Psychosis
Miosis
Nausea
Constipation
Coma

Question 14

What drugs can opiates interact with?

Answer 14

Other drugs that effect the CNS can increase the analgesic effect of opiates