Unit 2- Injectable Anesthetics

Question 1

General Anesthesia Effects

Answer 1

Unconsciousness, hyporeflexia, analgesia, skeletal muscle relaxation

Question 2

Anesthesia Principal Effect

Answer 2

Local vs general, sedative and tranquilizer vs analgesic, neuromuscular blockers, anticholinergics, reversal agents

Question 3

Anesthesia Chemistry

Answer 3

Barbiturate, non-barbiturate injectables, dissociative cyclohexylamines, inhalants

Question 4

Injectable Anesthetic MOA

Answer 4

Unknown, likely not one single receptor

Question 5

Injectable Anesthetic Uses

Answer 5

Produce unconsciousness alone, used with other agents, do not produce analgesia or muscle relaxation, titration method

Question 6

Titration Method

Answer 6

IV administration of drug until effect is seen

Question 7

Barbiturates

Answer 7

Sedative-hypnotic medications used for treatment of seizures, preoperative anxiety, and induction of anesthesia, high lipid solubility

Question 8

Ultra Short Barbiturates

Answer 8

Induce general anesthesia in dogs, cats, and horses: Thiopental and Methohexital

Question 9

Short Barbiturates

Answer 9

Induce general anesthesia and treat epilepsy in lab animals: Pentobarbital

Question 10

Long Acting Barbiturates

Answer 10

Used as anticonvulsant and sedative: Phenobarbital

Question 11

Oxybarbiturates

Answer 11

Methohexital, phenobarbital, and pentobarbital

Question 12

Thiobarbiturates

Answer 12

Thiopental and thiamylal are more lipid soluble

Question 13

Barbiturate MOA

Answer 13

Bind GABA gated Cl- channels and mimic inhibitory effects, cause CNS depression and loss of consciousness

Question 14

Barbiturate Uses

Answer 14

Rapid anesthetic induction, can be used alone for short procedures

Question 15

Thiopental Uses

Answer 15

To allow intubation and sustain wit inhalation anesthetic

Question 16

Methohexital Uses

Answer 16

To allow intubation and sustained with repeated doses or infusion

Question 17

Pharmacodynamics of Barbiturates

Answer 17

Non ionized, non protein bound, lipid soluble, blood distributes drug

Question 18

Lipid Solubility of Drugs

Answer 18

Affects ability to penetrate membranes, high solubility results in shorter action and rapid tissue redistribution

Question 19

Redistribution of Drugs

Answer 19

Distributed fastest to high perfusion tissue, effect occurs with drug in brain, drug leaves tissue when blood level drops, blood carries the drug to other tissues and it is eliminated

Question 20

Barbiturate Redistribution

Answer 20

Drug given IV, travels to brain, causes unconsciousness, when drug levels in brain are higher than blood, the drug moved back into blood, patient recovers, the drug is released from muscle and fat and metabolized

Question 21

Barbiturate Pharmacological Effects

Answer 21

Mild sedation to unconsciousness, excitement, cardiac depression, increased sensitivity to epinephrine, decreased respiratory rate, increased GI motility to decreased

Question 22

Thiopental Pharmacological Effects

Answer 22

Cardiac arrhythmia, brief apnea

Question 23

Pentobarbital Pharmacologic Effects

Answer 23

Shallow breaths

Question 24

Barbiturate Adverse Effects

Answer 24

Cardiac arrhythmia, heart skipping a beat, apnea, neonate respiratory depression, exaggerated potency in sighthounds, must be IV

Question 25

Barbiturate excitement during induction

Answer 25

Perivascular, slow rate of administration, stage II excitement if insufficient concentration in brain to induce stage III, administer more drug

Question 26

Barbiturate excitement during recovery

Answer 26

Pentobarbital causes paddling and vocalization, administer diazepam or pre anesthetics

Question 27

Barbiturate Drug Interactions

Answer 27

Enhance muscle relaxants, increase hepatic enzyme activity, enhanced effects when administered with chloramphenicol

Question 28

Thiopental

Answer 28

Ultra short acting, used in small animal and horses, crystalline powder is reconstituted

Question 29

Methohexital

Answer 29

Ultra short acting, higher lipid solubility than thiopental, safe in sighthound, used on unfasted animal, powder that is reconstituted

Question 30

Pentobarbital

Answer 30

Short acting, replaced by propofol, IP to rodents, treatment during status epilepticus, narrow margin of safety, used for euthanasia

Question 31

Propofol

Answer 31

Ultra short acting, good for outpatient, small animal, small ruminant, exotics, and neonates

Question 32

Propofol MOA

Answer 32

Activates GABAa receptors

Question 33

Propofol Use

Answer 33

Status epilepticus, short procedures or prior to inhalant anesthetic, short onset of action and duration, quick recovery, safe in head trauma, cats may not tolerate prolonged, safe in hepatic or kidney disease

Question 34

Propofol Handling

Answer 34

Poor storage characteristics, aqueous emulsion supports bacterial growth, more expensive

Question 35

Propofol Pharmacologic Effects

Answer 35

Depression, poor analgesia, euphoria, cardiac depression, transient hypotension, respiratory depression, apnea, twitching, appetite stimulant

Question 36

Propofol Adverse Effects

Answer 36

Excitement and muscle tremor during induction, movement resembling seizure, transient hypotension, apnea, pain with injection, can cause issues in cats

Question 37

Etomidate

Answer 37

Sedative hypnotic, used in animals with preexisting cardiac dysfunction, head trauma, or critical illness

Question 38

Etomidate MOA

Answer 38

Binds GABA receptor and enhances affinity of GABA

Question 39

Etomidate Adverse Effects

Answer 39

Pain and hemolysis, may inhibit cardiac contractility

Question 40

Etomidate Pharmacologic Effects

Answer 40

Decreased cerebral blood flow, metabolic rate, and oxygen consumption, minimal cardiac and respiratory depression, reduces plasma cortisol levels

Question 41

Alphaxalone

Answer 41

Synthetic neuroactive steroid

Question 42

Alphaxalone MOA

Answer 42

GABAa receptor agonist

Question 43

Alphaxalone Use

Answer 43

Short procedures, induction of anesthesia, use in dog and cat