Injectable anesthetics Flashcards
Definition of injectable anesthetic
a compound that by itself produces a state of general
anesthesia–> amnesia-unconsciousness-immobility ± analgesia
What is the MOA for all anesthetics except Ketamine?
GABA A receptor
Major implications for Barbiturates having a pH 10
Caustic (irritant) & long shelf life
T/F
Barbiturates are safe to use in C-section?
False, they are liposoluble so pass barrier causing fetal death
What injectable anesthetic is termed dissociative?
Cyclohexamine Derivative
CS- open eyes + light nystagmus
What is the only category of injectable anesthetics that provide anesthesia and analgesia
Cyclohexamine Derivative
Cyclohexamine Derivative moa
NMDA antagonist
What is a good sedative, hypnotic but does not provide analgesia
Propofol
Why should propofol be used with liver dysfunction?
Both hepatic & extra-hepatic metabolism
Alfaxalone is characterized as
neuroactive steroid providing hypnosis, myorelaxation but NO analgesia
Imidazole derivatives are characterized as
providing hypnosis, myorelaxation but NO analgesia
CV effect:
- Barbiturates
- Cyclohexamine derivatives
- Propofol
- Neuroactive steroids
- Imidazole
- Barbiturates: hypotension & reflex tachycardia (depressed contractility & vasodilation)
- Cyclohexamine derivatives: increased CO, O2 consumption, HR & MAP
- Propofol: mild CV depression, tachycardia (transient), arrhythmogenic, vasodilation & bradycardia
- Neuroactive steroids: BP maintained, temporary tachycardia and no arrhythmogenicity
- Imidazole: Cardio safe
What are respiratory effects of gaba receptor agonist?
dose- dependent ventilation depression & transient apnea
- NMDA antagonist do not have these effects!
Which injectable anesthetics maintain laryngeal function?
Barbiturates and cyclohexamine derivatives
Does Ketamine cause seizures?
No, but may lower seizure threshold
CNS effect:
- Barbiturates
- Cyclohexamine derivatives
- Propofol
- Neuroactive steroids
- Imidazole
- Barbiturates: decrease ICP & paradox excitement
- Cyclohexamine derivatives: increased cerebral blood flow & ICP
Which barbiturate predisposes patient to arrhythmias?
Thiobarbiturates
What active metabolite is responsible for excitement seen in prolonged ketamine CRI?
Norketamine
Which drug is choice for induction of C-section?
Propofol; it crosses barrier but is short lasting
Should propofol be used as the sole induction agent in adult horses?
NO
What is propofol infusion syndrome
can occur with prolonged infusion- observe metabolic acidosis, myopathy (rhabdomyopathy) & cardiomyopathy (arrhythmias)
Is propofol toxicity in cats:
No, but cats do have decreased glucoronidation, which is needed for metabolism of propofol and benzyl alcohol
- Phenol compound accumulate causing methemoglobinemia & Heinz bodies
- Benzyl alcohol accumulations and can cause acidosis & neurological signs
What are 3 things you should know about etomidate before use?
adrenal gland suppression, acute hemolysis & risk of thrombophlebitis
