Opioid 2 Flashcards
List the agonist model drugs (5)
- morphine
- methadone
- hydromorphone
- fentanyl
- tramadol
List the 2 agonist-antagonist opioids
- butorphanol
- buprenorphine
List the only full opioid antagonist
Naloxone2
Morphine MOA
Mu receptor agonist (new agonist)
PK of morphine
Liver metabolism & crosses placenta
Physical effects of morphine
Analgesia (primary use), emesis, miosis, decrease GI motility
Therapeutic Indications of Morphine
Tx acute pain, anesth. pre-med, antitussive
Adverse effects of morphine
Hyperexcitability, hypotension, cerebral hemorrhage, edema
What type of opioid is methdone
Synthetic
MOA of methadone
- Mu receptor agonist
- NMDA antagonist (good for deep nerve pain)
Physical effects of methadone
- slower elimination rate compared to morphine
- similar analgesic effect as morphine
Therapeutic indications
- pre-med
- analgesia
Adverse effect
- sedation
- vomit
- constipation
- resp. Depression
Hydromorphone MOA
Mu receptor agonist
Hydromorphone potency comparison to morphine
5x analgesic potency
Therapeutic indicators for hydromorphone
Analgesia, pre-med, anesthetic
Adverse effects of hydromorphone
Panting*, bradycard., dose-dependent excitement, cerebral hemorrhage, edema
Why is hydromorphone being increasingly used in vet med? What is it replacing?
- replacing oxymorphone
- being used b/c oxymorphone is expensive & has availability issues
T or F: Fentanyl is a synthetic opioid
True
What are the units used in fentanyl dosing?
Mcg
MOA of fentanyl
Mu receptor agonist
Pharmacokinetics of fentanyl
- faster onset than morphine
- shorter duration of action
- more potent (75-125x)
Therapeutic indications of fentanyl (3)
Continuous infusion analgesia, K9 inductor, neuropetanalgesia
Adverse effects of fentanyl
Motor response, panting, pooping, farts, bradycardia, salivation
Tramadol is a synthetic analog of…
Codeine
MOA of tramadol
Mu receptor agonist (WEAK), inhibits serotonin & NE uptake
Pharmacokinetics for tramadol
- active metabolite: desmethyltramadol
- exaggerated opiate effects may be seen in cats b/c they can’t glucuronidate
Therapeutic indications
- analgesic
- antitussive in small animals
Can tramadol be reversed?
Yes, only partially by nalaxone
MOA of butorphanol
- high affinity for mu receptors, but no activity
- high affinity for kappa receptors, moderate agonist activity
- 4-7x stronger than morphine
Is butorphanol an agonist or antagonist?
Neither, its an agonist-antagonist
(Both properties)
Pharm. effects of butorphanol
Analgesia
Therapeutic indicators
Opioid reversal, analgesic, antitussive
What effect does butorphanol’s short duration of activity have on its usage?
Limits it (b/c 0.5-6 hrs)
Can butorphanol be reversed?
- yes, but it is difficult b/c of its high receptor affinity
The most generally useful anlagesic in K9 & cats is
Buprenorphine
(30x stronger than morphine)
MOA of buprenorphine
- high affinity for mu receptors, but partial agonist
- kappa receptor antagonist
Pharmacokinetics for butorphanol
Longer duration of action than other opioids
Therapeutic indications for buprenorphine
- analgesia for mild-mod. Pain in small animals
- cats can have buccal or transmucosal admin.
Simbadol
- long acting, SQ buprenorphine
- cats only
- lasts 24 hrs; admin SID
- for surgical pain
Zorbium
- transdermal solution
- for cats
- lasts for 4 days
- single, in clinic dose
Opiate antagonists are…
Pure antagonists; no agonist activity
MOA naloxone
- high affinity for mu receptors
(Higher doses reverse DOP and KOP)
Pharmacokinetics of naloxone
- short duration of action, so may need repeated admin
Therapeutic indications of naloxone
- Reverse opioid induced respiratory depression & shock Tx
- given IV, IM, IN (if no IN response after 5 mins, repeat)
- extralabel use in K9 & cats
- not regulated by CSA
Adverse effects of naloxone
- CNS sedation
- excitement in horses and cats
- resp. Depression
- bradycardia
- sedation
- contraindicated shock, severe cranial trauma and diseases assc. w/ resp. Compromise
Tolerance and dependence of naloxone
- aren’t used long enough in vet med to cause tolerance/depend.
- if P is on opiates > 5-7 days, then withdrawal signs may be seen after stopping meds
- DON’T CUT OFF COLD TURKEY, WEAN P OFF OPIOID
Schedule I drugs
No medical benefit/use
Schedule II-IV drugs
High to low abuse potential
Schedule V drugs
Lower potential for abuse compared to schedule IV
Most pure opioid agonists (i.e. morphine) are classified as
Schedule II
Buprenorphine is a Schedule….
Schedule III
Butorphanol is Schedule…
IV
