Opioids

Question 1

What are opioids most effective in controlling?

Answer 1

peripoerative and acute pain.

Question 2

What pathways do opioids act on?

Answer 2

perception, modulation, and transduction

Question 3

What are the 3 types of opioid receptors and where are they located?

Answer 3

mu, kappa, and delta. They are located in the brain and spinal cord.

Question 4

Which receptors are most commonly affected by opioid drugs?

Answer 4

mu receptors

Question 5

Which mu receptor affects supraspinal analgesia?

Answer 5

mu 1

Question 6

Which mu receptor affects spinal analgesia?

Answer 6

mu2

Question 7

What is the MOA of opioid agonists on the mu receptor?

Answer 7

They inhibit presynaptic release of substance P and other excitatory neurotransmitters and inhibit post-synaptic response to excitatory neurotransmitters

Question 8

What is the most common for of administration of opioids?

Answer 8

IV or IM

Question 9

Why are opioids not administered orally?

Answer 9

Because they undergo an extensive first pass effect, significantly reducing their bioavailability.

Question 10

T/F: opioids can cross the BBB and the placenta

Answer 10

True

Question 11

How are opioids metabolized? How are they excreted?

Answer 11

They are metabolized by conjugation to glucuronic acid and they are renally excreted in the urine

Question 12

Which full mu agonist is used in epidurals, lasts several hours, and has a risk of histamine release especially in dogs when given IV?

Answer 12

morphine

Question 13

This full mu agonist is used more commonly than morphine, has a similar duration of action and less risk of histamine release?

Answer 13

hydromorphone

Question 14

This drug is similar to hydro but may be less emetogenic. It can cause smoother sedation in cats and pediatric patients

Answer 14

oxymorphone

Question 15

This drug is the most potent full mu agonist, it last about 30 minutes, and is available transdermally

Answer 15

fentanyl

Question 16

This drug is used in wildlife and is very potent. Must have antagonist on hand

Answer 16

carfentanil/eterphine(M99)

Question 17

This drug has a ceiling effect, is more potent and has a longer duration of action than morphine, and can be administered IV, IM, and transmucosally

Answer 17

buprenorphine (partial mu agonist)

Question 18

This drug has a lower ceiling effect than mu agonists, is one of the more commonly used opioids in equines, can be administered IV, IM, SC, and PO, and has greater antitussive effects than pure mu agonists.

Answer 18

Butorphanol (torb)

Question 19

T/F: butorphanol is better for somatic.

Answer 19

False. It may be better for visceral pain

Question 20

How do opioid agonists affect thermoregulation?

Answer 20

they cause hypothermia in dogs, rabbits, and monkeys, while causing hyperthermia in cats, ruminants, and horses.

Question 21

What is apomorphine used for?

Answer 21

emesis in dogs

Question 22

What effects do opioid agonists have on the respiratory system?

Answer 22

they can cause dose-dependent respiratory depression (mu2) that can lead to decreased sensitivity of rising PaCO2 and thus hypoventilation.

Question 23

What is the most important CV effect caused by opioid agonists in dogs?

Answer 23

centrally-mediated bradycardia and hypotension due to vasodilation (mu1)

Question 24

T/F: opioid agonists can cause urinary retention

Answer 24

True

Question 25

Which opioid agonist produces the most sedative effect?

Answer 25

kappa agonists

Question 26

When may Naloxone be used? What is something to be aware of when using naloxone??

Answer 26

Naloxone is used in cases of opioid toxicity. It is short acting, so you may need to repeat doses until the opioid is gone.

Question 27

T/F: Naloxone will reverse the opioid effects, but not the analgesic effects.

Answer 27

False.

Question 28

This drug is a partial mu agonist used for short-term post op pain management, can lower seizure threshold and also inhibits the re-uptake of serotonin and NE

Answer 28

tramadol

Question 29

This semisynthetic opioid is used orally as an anti-tussive

Answer 29

hydrocodone

Question 30

What is the opioid with the most potent anti-diarrheal effect?

Answer 30

loperamide