Pre-anesthetic Medication and Induction Agents Flashcards
There are advantages and disadvantages to preanesthetic analgesia and sedation. What are 3 advantages?
- Chemical restraint
- Decreased stress + decreased catecholamines = Decreased risk of arrhythmia
- Decreased induction and inhalant doses = Decreased dependent CV/respiratory depression
- Pre-emptive analgesia
There are advantages and disadvantages to preanesthetic analgesia and sedation. What are 3 disadvantages?
- Bradycardia (opioids & alpha 2 agonists)
- Hypotension (acepromazine)
- Excitation (opioids & benxodiazepines)
There are 5 Mu-opioid and kappa agonists. Name 3 of them.
- Hydromorphone
- Fentanyl
- Morphine
- Methadone
- Oxymorphone
What type of agonist is Buprenorphine?
Partial Mu agonist
What type of agonist/antagonist is Butorphanol?
Mixed kappa agonist & mu antagonist
What are the 2 reversal agents for opioid analgesics (hydromorphone, fentanyl, morphine, methadone, oxymorphone, butorphanol, buprenorphine)?
Naloxone & naltrexone
Opioids can have mild cardiovascular effects. Which factor within the cardiovascular system is decreased by these drugs? What is increased to cause these effects?
Decreased heart rate due to increased vagal tone
True or False: Opioids increase the MAC of an inhalant.
FALSE: Opioids decrease the MAC of an inhalant
True or False: Opioids can cause respiratory depression.
TRUE
Which opioid analgesic is a partial agonist?
Buprenorphine
Which opioid analgesic is a mixed agonist/antagonist?
Butorphanol
Which opioid analgesics are FULL mu-opioid agonists?
Hydromorphone, Fentanyl, Morphine, Oxymorphone, & Methadone
True or False: Butorphanol has a “ceiling effect”.
TRUE
Compared to mu-opioid agonists, Butorphanol elicits less what?
- Panting
- Bradycardia
- Respiratory depression
- Analgesia
- Nausea (no vomiting)
True or False: Buprenorphine has a “ceiling effect”.
TRUE
In dogs and cats, what is the dose in mg/kg for Butorphanol?
0.2 - 0.4 mg/kg
How long does sedation last under Butorphanol?
1 - 2 hours
How long does sedation last under Buprenorphine?
Dogs: 4 - 10 hours
Cats: 6 - 12 hours
Which of the following has a slow onset, Butorphanol or Buprenorphine? How long is that onset?
Buprenorphine: 30 - 45 minutes
In small animals, what is the Buprenorphine dose in mg/kg?
0.1 - 0.4 mg/kg
Compared to FULL mu-opioid agonists, Buprenorphine elicits less what?
- Respiratory depression
- Panting
- Bradycardia
- Analgesia
- Nausea
What is the duration of action of hydromorphone and oxymorphone?
2 - 4 hours
What is the duration of action of morphine and methadone?
4 - 6 hours
How long is Fentanyl’s duration of action?
Short: 15 to 30 minutes
True or False: ALL full mu-opioid agonists cause nausea and vomting.
FALSE: Fentanyl does NOT cause vomiting
Which of the mu agonists causes the greatest respiratory depression?
Fentanyl
What type of agonist or antagonist is Acepromazine?
Alpha 1 antagonist
What is the onset of action of Acepromazine? What is the duration?
Onset: 20 - 30 minutes
Duration: 4 - 6 hours
What are the cardiovascular side effects of Acepromazine?
Vasodilation
Hypotension
Bradycardia
Which of the sedative/tranquilizer drugs is NON-REVERSIBLE?
Acepromazine
True or False: Acepromazine causes seizures.
FALSE: Acepromazine may actually decrease the risk of seizure activity by decreasing excitation out of surgery
What type of agonist or antagonist is Dexmedetomidine?
Alpha 2 agonist
What is the time till onset of action for Dexmedetomidine? What is the duration?
Onset: 5 minutes
Duration: 30 - 60 minutes
What is the reversal agent for Dexmedetomidine?
Atipamazole
For what type of patients would you reserve Dexmedetomidine?
Very painful, fearful, aggressive patients
These alpha-2 agonists are used in horses: xylazine, detomidine, ad romifidine. What are their reversal agents?
Yohimbine & tolazoline
For which patients should Benzodiazepines like Diazepam and Midazolam be reserved?
Pediatric and geriatric patients and the critically ill
What is the reversal agent for Diazepam or Midazolam?
Flumazenil
Diazepam contains propylene glycol, causing which 3 unwanted effects?
- Pain on injection
- Poor absorption
- Toxicity at high doses
What is the dosage for Midazolam to be given IM or IV?
0.1 - 0.2 mg/kg
Atropine can be used for emergencies because of its quick onset of action. What is its time of onset IM and IV?
IM = 5 minutes
IV = 1 minute
How long is Atropine’s duration of action?
60 - 90 minutes
What is the onset of action for Glycopyrrolate? What is its duration?
Onset: 3 - 5 minutes
Duration: 2 - 4 hours
