Opiates, antagonists, and applications

Question 1

What are the two types of opiates?

Answer 1

Endogenous

Plant or synthetic: act at receptors for endogenous opiods

Question 2

What are opioids?

Answer 2

Alkaloids from the exudate of seed capsules of the poppy plant

Question 3

Define narcosis:

Answer 3

reversible CNS depression with stupor or insensibility produced by drugs

Question 4

Define neuroleptanalgesia and what two drugs can be used to accomplish this

Answer 4

Sedation plus hypnosis

Opioid + tranquilizer

Question 5

What are the four different receptors of opioids? Which is the most important?

Answer 5

Mu receptor**
Delta receptor
Kappa receptor
Sigma receptor

Question 6

What effects does the Mu receptor control?

Answer 6

Analgesia and euphoria

Respiratory depression, inhibition of GI motility, and pupil effects

Question 7

What effects does delta receptor have when activated?

Answer 7

Cardiovascular and respiratory depression

Analgesia at spinal level

Question 8

What effects does the kappa receptor have?

Answer 8

Analgesia, primarily at spinal level
May be more beneficial for visceral pain
Sedation, dysphoria, psychomimetic effects

Question 9

What are the effects of opiates on the CNS?

Answer 9

depression, sedation, and/or euphoria

Analgesia, may block cough, pain threshold is increased centrally

Question 10

What are the effects of opiates on the respiratory tract?

Answer 10

Overall depression

Increases threshold for CO2, bronchoconstriction in dog

Question 11

What are the effects of opiates on CV system?

Answer 11

vasodilation, bradycardia, drop in blood pressure

Question 12

When would use of opiates be contraindicated?

Answer 12

Patient with hypotension

Question 13

What are the effects of opiates on muscle?

Answer 13

Stimulation/rigidity

Question 14

What are the effects of opiates on renal?

Answer 14

Increased ADH = increased H2O reabsorption

Question 15

What are the effects of opiates on GI?

Answer 15

Reduced motility, secretions, and peristalsis

Increase tone of smooth muscle and may see emesis in some animals

Question 16

What are the effects of opiates on the behavior of dogs? cats? cattle?

Answer 16

Depression in dogs and monkeys

Excitation in everything else (cats, horse, goat, sheep, pig, and cattle)

Question 17

What are the effects of opiates on thermoregulation? What species does it often raise the body temp most in?

Answer 17

Increase: CATS

Hypothermic in some: rabbits, dogs, and monkeys

Question 18

What are the ways opiates are eliminated from the body? What form is it in?

Answer 18

Glomerular filtration or bile

In the GLucuronide form (this is also the more potent form)

Question 19

Describe the different categories of DEA controlled drugs:

Answer 19

Schedule 1: no currently accepted medical use
Schedule 2: high potential for abuse. Must be ordered on special form
Schedule 3, 4, and 5: only require a DEA number

Question 20

What receptors does Apomorphine act on? What is it very good at?

Answer 20

Acts on dopamine receptors

Ecellent inducer of emesis in dogs

Question 21

T/F Apomorphine should not be used by itself for narcosis

Answer 21

TRUE; does not do this well on its own

Question 22

T/F most synthetic opiates are mu or kappa agonists making them good for analgesia

Answer 22

TRUE

Question 23

What is a benefit of Hydromorphine when compared to morphone?

Answer 23

Less nausea, emesis, or GI effects

Question 24

What are some benefits of using Buprenorphine over morphine?

Answer 24

Longer acting, less GI or respiratory effects

Question 25

What species are more susceptible to excitement from opiates?

Answer 25

Cats and horses

Question 26

What species is the half-life of opiates longer/

Answer 26

Cats; decreased biotransformation in liver

Question 27

What species is more susceptible to emesis with opiate use?

Answer 27

Dogs

Question 28

What are some uses for opiates in the veterinary setting?

Answer 28

``` Pain management Pre-anesthetic Neuroleptanalgesia (Short duration) Chemical restraint/sedation Emesis Treatment of diarrhea ```

Question 29

What are some situations that would would not consider using opioids?

Answer 29

``` Shock (increases hypotension) Convulsive disorders (enhances seizures) Head injury (increases IC pressure) Uremia Toxemia (Impaired excretion of urine) Liver failure Young animals (Decreased biotransformation) Strychnine ```

Question 30

T/F Opioid antagonists are very fast acting

Answer 30

TRUe

Question 31

T/F Opioid antagonists can reverse hypotension in shock

Answer 31

TRUE

Question 32

Why would you not want to use opioid antagonists to reverse hypotension in shock?

Answer 32

They also block mu receptors for analgesia

Question 33

What are the most common opioid antagonists used?

Answer 33

Naloxone and naltrexone

Question 34

What is re-narcotization?

Answer 34

Major concern with potent opioids Involves giving an antagonist that is shorter acting than the opioid agonist