Barbiturates

Question 1

which barbiturates are ultra-short, short, and long acting

Answer 1

ultra: methohexital (oxybarbituate) and thiopental (thiobarbituate)
short: pentobarbital (oxy.)
long: phenobarbital (oxy.)

Question 2

how rapid a barbiturate takes effect and for how long depends on

Answer 2

lipid solubility (the more soluble the faster the onset of action; passes to brain quicker)

Question 3

how drug goes from the brain to other areas of the body

Answer 3

moves down concentration gradients

Question 4

do barbiturates cause analgesia

Answer 4

no

Question 5

effects on CNS

Answer 5

depresses (causes excitement in lower doses and slower administration)

Question 6

becase barbiturates have high lipid solubility they move to the brain and take effect (slowly/quickly) and leave brain (slowly/quickly)

Answer 6

quickly/ quickly

Question 7

cardiac effects

Answer 7

decreased CO, hypotension (observe MM), arrythmia in stressed animals bc stimulation of symp NS

Question 8

Respiratory effects

Answer 8

decreased RR, decreased tidal volume, can cause apnea after induction if given too fast or too high of a dose, resp arrest.

Question 9

perivascular leakage of barbiturates causes

Answer 9

tissue irritation, pain, swelling, necrosis, slouhging tissue

Question 10

pentobarbital uses

Answer 10

treat status epilepticus, anes agent

Question 11

drug in euthanasia solutions

Answer 11

pentobarbital

Question 12

ultra-short acting barbiturates

Answer 12

thiopental, methohexital

Question 13

short acting barbiturates

Answer 13

pentobarbital

Question 14

long acting barbiturates

Answer 14

phenobarbital

Question 15

thiopental duration

Answer 15

10-15 min

Question 16

methohexital duration

Answer 16

5-10min

Question 17

caution cases for barbiturates

Answer 17

thin animals like sighthounds (v little fat so stays in brain longer), hypotensive, hepatic/renal disease (is metabolized and excreted eventually), hypothermic or critically ill (slow metabolism prolonging effects)

Question 18

phenobarbital uses

Answer 18

anticonvulsant, sedative, stop status epilepticus (IV), PO prevents seizures long term

Question 19

which barbiturate causes no anesthesia

Answer 19

Phenobarbital`

Question 20

route of admin for pentobarbital

Answer 20

IV, can also be given via intraperitoneal or intracardiac injection if anesthetized

Question 21

how long it takes for methohexital and thiopental to take effect

Answer 21

30-60 sec

Question 22

how we adminster methohexital or thiopental to effect

Answer 22

start at half dose, then titrate the rest to effect

Question 23

why we dont inject air into a bottle of barbiturate

Answer 23

precipitate may form

Question 24

what happens if we give a pregnant animal a barbiturate

Answer 24

is able to cross placenta and anesthetize babies (greater effects on fetus than mother)