opioids

Question 1

Pain control can be provided by:

Answer 1

1. local anesthetics

2. opioids

Question 2

Most induction agents or inhaled agents

Answer 2

do not provide pain relief (ketamine provides a little pain relief)

Question 3

Opiate

Answer 3

is the term used to designate drugs derived from opium

Question 4

Opioid

Answer 4

refers to all substances natural (morphine) and synthetic (fentanyl) and semi-synthetic (heroin) that bind to opioid receptors and produce an agonist effect

Question 5

Structure of opioids

Answer 5

1. Phenanthrenes- morphine, codeine, thebaine

2. Benzylisoquinolones- (lack analgesic activity)- papaverine & noscapine

Question 6

Opioid Classification

Answer 6

1. naturally occurring
2. semisynthetic
3. synthetic

Question 7

Naturally occurring opioid

Answer 7

Morphine

Question 8

Semisynthetic opioids

Answer 8

analogs of morphine (difference in changing the structure slightly

1. heroin
2. hydromorphone
3. codeine

Question 9

Synthetic opioids

Answer 9

Exogenous (4 groups)

1. Morphinan derivatives
2. Diphenyl derivatives
3. Benzomorphans
4. Phenylpiperidines

Question 10

Morphinan derivatives

Answer 10

• agonist-antagonists
  1. Levorphenol
  2. Butorphenol

Question 11

Diphenyl derivatives

Answer 11

Methadone

Question 12

Benzomorphans

Answer 12

1. Phenazocine
2. Pentazocine
   * *used more for vasodilation than for pain

Question 13

Phenylpiperidines

Answer 13

VERY COMMON IN THE OR

1. Meperidine
2. Fentanyl
3. Alfentanil
4. Sufentanil
5. Remifentanil

Question 14

Further classification of opioids

Answer 14

1. agonist
2. partial agonist (weaker drugs)
   - buprenorphine: regardless of dose- can’t produce full mu receptor effects like morphine
3. Mixed agonist/antagonist (much better option that antagonist when reversing)
   - nalbuphine- agonist at kappa receptor and antagonist at mu receptor= reverses respiratory depression while still acting on kappa
4. Antagonist
   - naloxone

Question 15

Opiate Receptors

Answer 15

1973- researchers described the presence of receptors
1975- endogenous agonists were identified
1. enkephalins
2. endorphins
3. dynorphins

Question 16

Opioid Receptors

Answer 16

1980s- existence of opioid receptor and began naming them (mu, kappa, delta)— most drugs aren’t specific and work all of the receptors

• believed that synthetic opioids mimic action of endogenous opioids by binding to the opioid receptors
• when binding occurs= activation of pain modulating systems in brain and spinal cord
• *antinociceptive- inhibits excitatory neurotransmitters (is substance P)

Question 17

Mu receptor

Answer 17

There are 2 subtypes (mu-1 and mu-2)
Mu-3 are thought to be involved in the immune process

ALL ENDOGENOUS AND EXOGENOUS AGONISTS ACT ON MU RECEPTORS
-mu receptors are primarily in the brain and spinal cord

Question 18

Mu-1 receptor

Answer 18

Effects:

1. Analgesia: supraspinal (mainly), spinal (lesser)
2. Euphoria
3. Miosis
4. . Bradycardia
5. Hypothermia
6. Urinary retention
7. Low abuse potential

Agonists: morphine, all endogenous, exogenous, synthetic opioids
Antagonists: naloxone, naltrexone, nalmefene

Question 19

Mu-2 receptor

Answer 19

Effects:

1. Analgesia: spinal analgesia
2. hypoventilation
3. MARKED constipation
4. physical dependence

Agonists: morphine all endogenous, exogenous, synthetic opioids
Antagonists: naloxone, naltrexone, nalmefene

Question 20

Kappa receptor

Answer 20

Effects:

1. Analgesia: supraspinal and spinal (equally)
2. Dysphoria
3. Sedation
4. Miosis
5. Diuresis
6. Low abuse potential

Agonists: Dynorphins
Antagonists: naloxone, naltrexone, nalmefene

Question 21

Delta receptor

Answer 21

Effects:

1. Analgesia: supraspinal and spinal (equally)
2. Hypoventilation
3. Urinary retention
4. MINIMAL constipation
5. Physical dependence

Agonists: Enkephalins
Antagonists: naloxone, naltrexone, nalmefene