Opioids Flashcards
What are opioids most effective in controlling?
peripoerative and acute pain.
What pathways do opioids act on?
perception, modulation, and transduction
What are the 3 types of opioid receptors and where are they located?
mu, kappa, and delta. They are located in the brain and spinal cord.
Which receptors are most commonly affected by opioid drugs?
mu receptors
Which mu receptor affects supraspinal analgesia?
mu 1
Which mu receptor affects spinal analgesia?
mu2
What is the MOA of opioid agonists on the mu receptor?
They inhibit presynaptic release of substance P and other excitatory neurotransmitters and inhibit post-synaptic response to excitatory neurotransmitters
What is the most common for of administration of opioids?
IV or IM
Why are opioids not administered orally?
Because they undergo an extensive first pass effect, significantly reducing their bioavailability.
T/F: opioids can cross the BBB and the placenta
True
How are opioids metabolized? How are they excreted?
They are metabolized by conjugation to glucuronic acid and they are renally excreted in the urine
Which full mu agonist is used in epidurals, lasts several hours, and has a risk of histamine release especially in dogs when given IV?
morphine
This full mu agonist is used more commonly than morphine, has a similar duration of action and less risk of histamine release?
hydromorphone
This drug is similar to hydro but may be less emetogenic. It can cause smoother sedation in cats and pediatric patients
oxymorphone
This drug is the most potent full mu agonist, it last about 30 minutes, and is available transdermally
fentanyl
This drug is used in wildlife and is very potent. Must have antagonist on hand
carfentanil/eterphine(M99)
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
buprenorphine (partial mu agonist)
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.
Butorphanol (torb)
T/F: butorphanol is better for somatic.
False. It may be better for visceral pain
How do opioid agonists affect thermoregulation?
they cause hypothermia in dogs, rabbits, and monkeys, while causing hyperthermia in cats, ruminants, and horses.
What is apomorphine used for?
emesis in dogs
What effects do opioid agonists have on the respiratory system?
they can cause dose-dependent respiratory depression (mu2) that can lead to decreased sensitivity of rising PaCO2 and thus hypoventilation.
What is the most important CV effect caused by opioid agonists in dogs?
centrally-mediated bradycardia and hypotension due to vasodilation (mu1)
T/F: opioid agonists can cause urinary retention
True
Which opioid agonist produces the most sedative effect?
kappa agonists
When may Naloxone be used? What is something to be aware of when using naloxone??
Naloxone is used in cases of opioid toxicity. It is short acting, so you may need to repeat doses until the opioid is gone.
T/F: Naloxone will reverse the opioid effects, but not the analgesic effects.
False.
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
tramadol
This semisynthetic opioid is used orally as an anti-tussive
hydrocodone
What is the opioid with the most potent anti-diarrheal effect?
loperamide
