What is the duration of action of Thiopental and the onset of action?
Why is Thiopental not good to use in sighthounds and thin athletic dogs?
High lipid slubility
Recovery occurs as drug is redistributed to muscle and fat, followed by excretion via hepatic metabolism.
Recovery may be prolonged in sighthounds and thin athletic dogs.
Complete recovery usually takes 1-2hrs
Supplied as a crystalline powder in multidose vials for reconstitution. No bacteriostatic agent present use caution when reconstituting
Strongly alkaline solution can cause severe tissue damage if injected perivascularly. Use IV catheter. If perivascular injection occurs infiltrate with equal volume of saline +/- 2% lidocaine (can kill the tissue)
Usually bolus 1/3-1/2 initial dose over 10-15 sec. the titrate slowly to effect.
Debilitated animals may only require 80% of the calcualted dose
Don't use on hypoproteinemic or acidotic animals
Thiobarbiturates decrease intracranial and tnreocular pressure
Causes splenic engorgemnetconseder sugical prcedure, diagnostic test.( in case in need of explaratory)
What is the duration of action and onset of action of Methylated oxybarbiturates?
More rapidly metabolixed than Thiopental recovery with 30 minutes
Can be used in sight hounds
Comes as powder, reconstitue to 1% solution 6wk shelf life
Less irritaiting than thiopental if injected perivascularly
Associated with excitement in recovery especially if used alone. Recommend premedication with a sedativie or tranquilizer
May see seizures in induction or recovery use diazepan to control
Don't use in animals with pre-existing CNS disease
What drugs are in the cyclohexamines family?
What does cycloheximines do?
Disrupt nerve condition with in the cerebrum, causing selective CNS stimulation
What are the contraindications of cycloheximines?
patients with seizures disorders
What do you see with the use of cyclohexamines, which are ketamine, Phencyclidine, Tiletamine?
Exaggerated reflexes- brisk palpebral, pedal and corneal
Persistence of pharyngeal and laryngeal reflexes (weak)
Marked sensitivity to sound, light and sensory stimuli, especially in recovery.
Muscle tone increased, sometimes rigid
May see apneustic respiration-insipiration followed by a prolonged pause and short expiration
Does cyclohexamines depress cardiac reat or function?
No, see increased heart rate, myocardial function and blood pressure due to release of epinephrine
Use in caution if pre-existing arryhthmias or cardiac disease.
Are cyclohexamines good analgesia?
No, because it only gives analgesia to the skin and limbs not to visceral.
Eliminated by metabolism in liver, or by renal excretion-renal excretion-specie dependent
Eyes remain open, pupil remains central and dilated, nystagmus may occur
May cause increased salivation and lacrimation
Irritating on injection (IM, Perivascular) can give IM or IV
May increase CSF pressure-contraindicated in head trauma
Licensed for use in cats, also used in dogs, birds, horses, and exotics
Excreted primarily through kidney in cats, liver in dogs
Schedule III Controlled substance- Records, logs
What is the onset of action and recovery for ketamine?
Onset: 90 sec when given IV
Recovery usually occurs with 2-6hrs
Why do dogs recover more quickly than cats with Ketamine?
Because dogs metabolize it in the liver
Why would you combine Ketamine with a tranquilezer?
To aid muscle relaxation and prevent excitement during recovery
Very popular in cats and dogs. Minimal cardiac depression, good muscle relaxation, superior recovery, less risk of seizure, some analgesia. Can also use Ketamine-Midazolam
Most frequently used in equine anesthesia
May see bradycardia, heart block, seizures in recovery
Used in cats less muscle relaxation
Only availabe with zolazepam in the drug telazol
Sold as a powder which must be reconstituted
Schedule III controlled substance
Causes less apneustic respiration then ketamine
Telazol may be used IV, IM, SQ
Also used in wildlife
Disadvantage is long, difficult recoveries
What is a neuroleptanalgesia?
Not a method of anesthesia but a state of calmness with some dissociation from the environmetn; analgesia; and lack of aggressiveness
What is neuroleptanalgesia made?
Its a combination of opiodand tranquilizing agent, frequently mixed in same syringe except for diazepam
Give examples of neuroleptanalgesia
Morphine and Acepromazine
Oxymorphone and Acepromazine
Butorphanol and Acepromazine
What are neuroleptanalgesia used for?
Can be used for sedation, or for induction of anesthesia
Nonbarbiturate, non dissociative, intravenous anesthetic agent which is ultra-short acting
Used for short procedures or anesthetic induction, also control of status epiepticus
Oil in water emulsion with a milky apperance- safe IV
Expensive, preservative presnt-Use strict aseptic technique currently 28 days shelf life
No analgesic effect
Safe for use in sighthounds
What is the onset and duration of propofol?
How does propofol redistributes?
Redistibutes from brain to muscle and fat, but metabolized 5-10times faster than thiopental.
Can be repeated as needed to maintain anesthesia, or give infusion
What are the adverse effects of propofol?
Respiratory deppression- see apnea if injected rapidly IV