CNS

Question 1

what is primary type of action potential transmission in CNS, chemical or electrical transmission

Answer 1

chemical

Question 2

influx of which ion into the presynaptic membrane stimulates NT exocytosis

Answer 2

calcium ion (Ca2+)

Question 3

is changing the concentration of. NT OR up/downregulating a receptor a direct or indirect receptor interaction

Answer 3

indirect

Question 4

are CNS drugs generally extremely selective for their target

Answer 4

no, they are RELATIVELY selective for their target

Question 5

are both initial and delayed responses important for ultimate clinical effect

Answer 5

yes

Question 6

the ability of a drug to penetrate the lipophilic BBB is critical to its activity in the CNS. what is often involved in the BBB penetration?

Answer 6

active metabolites (which may have a longer half-life than the parent drug)

Question 7

what are the 5 classes of drugs that affect the CNS

Answer 7

anesthetics, analgesics, tranquilizers and sedatives, anti-depressants and anti-anxiety drugs, anti-epileptic drugs

Question 8

what is the goal of anti-epileptic therapy

Answer 8

balance reduction of seizures with quality of life for patient

Question 9

what is a major inhibitory NT in CNS

Answer 9

GABA

Question 10

this first-line AED is moderately lipophilic (can cross BBB), has kinetics change in first few days, and there is considerable variation in serum concentration for any specific dose

Answer 10

phenobarbital

Question 11

name 3 adverse effects of phenobarbital

Answer 11

behaviour changes (sedation or hyper excitability), immune mediated anemia/neutropenia, acute hepatotoxicity, polydipsia, polyphasic, hepatotoxicity, decreased serum T4 concentrations

Question 12

what should you know about drugs that inhibit cytochrome P450 enzymes, eg. chloramphenicol, cimetidine, ketoconazole

Answer 12

can cause phenobarbital toxicity

Question 13

what does the induction of cytochromeP450 enzymes by phenobarbital change

Answer 13

change the PK of some other drugs

Question 14

why is therapeutic drug monitoring of phenobarbital important

Answer 14

serum concentrations at a given dose vary between individuals, so dose adjustments often needed

Question 15

when should you monitor concentration of phenobarbital in patients

Answer 15

monitor concentration to first steady state concentration time point (2 weeks), again at first steady state clearance time point (6 weeks), monitor liver function every 6 months

Question 16

this AED has an extremely long half life (15 days dog, 10 days cat) so is very slow to reach steady state, and no peak or trough. It is cleared really (no hepatic or protein binding) so patients with kidney disease may need dose reduction

Answer 16

KBr potassium bromide

Question 17

when is steady state reached in KBr? when should serum drug concentrations be monitored?

Answer 17

3 months. monitor at 1 month, 3 months, annually (or sooner if evidence of toxicity or ineffectiveness)

Question 18

this AED is primarily an add-on treatment and has a short half-life

Answer 18

levetiracetam

Question 19

this benzodiazepine AED is used to treat acute seizures and status epileptics and impractical for long-term therapy in dogs due to short half-life, tolerance/dependance possibility, and abuse potential

Answer 19

diazepam

Question 20

dog is emergency seizuring! what is the preferred emergency seizure drug and why? what is route of administration?

Answer 20

diazepam, it is more lipophilic that other benzodiazepines. can give per rectum (owner can use this route), orally, or IV, but not IM

Question 21

this AED has a short half-life in dogs (2 hours) so no accumulation with typical chronic use, high therapeutic index, and no therapeutic monitoring is needed

Answer 21

imepitoin

Question 22

potential behavioural consequence of behaviour modifying drugs

Answer 22

aggression

Question 23

behaviour modifying drugs and antidepressants take how long to exert full effects?

Answer 23

several weeks

Question 24

is it necessary to taper behaviour modifying drugs after long-term administration

Answer 24

yes

Question 25

name 3 general clinical effects of benzodiazepines

Answer 25

anxiolytic, anterograde amnesia (good for pre-anesthetic), anticonvulsant; also sedative and hypnotic at higher effects, muscle relaxant, appetite stimulant

Question 26

different effects of different drugs in benzodiazepine class are due to what?

Answer 26

variations in the GABA receptor

Question 27

what are 3 PK and PD considerations about diazepines?

Answer 27

chronic administration can cause GABA receptor down-regulation, tolerance may occur, and gradual tapering is needed after chronic administration to prevent discontinuation syndrome

Question 28

there are many different subtypes of serotonin receptors; are they presynaptic or postsynaptic?

Answer 28

some are presynaptic and some are postsynaptic

Question 29

buspirone and SSRIs desensitize which receptor

Answer 29

5-HT1A

Question 29

buspirone and SSRIs desensitize which receptor

Answer 29

5-HT1A

Question 30

name 4 types of antidepressant drugs and an example drug from each type

Answer 30

SSRIs (selective serotonin reuptake inhibitors), eg. fluoxetine; tricyclic antidepressants, eg. clomipramine; MAOs (monoamine oxidase inhibitors), eg. selegiline HCl; atypical antidepressants, eg. trazodone

Question 31

you are starting a kittycat on antidepressants. should you start at the low or high end of a dose? how long should you expect to see a response?

Answer 31

low end of dose (in order to assess response to minimize adverse effects). at least 2 weeks, but potentially 4-6 weeks to see full response

Question 32

if you increase SSRI plasma concentrations, what change will you see in the clinical effect

Answer 32

there is no relationship between SSRU plasma concentrations and clinical effect

Question 33

this most commonly used SSRI requires great caution if combined with MAOIs due to the risk of serotonin syndrome

Answer 33

fluoxetine

Question 34

this fluoxetine drug (proprietary name) is specifically approved for treating separation anxiety

Answer 34

Reconcile

Question 35

what is the effect of tricyclic antidepressants on serotonin, norepinephrine, acetylcholine, and histamine

Answer 35

inhibit serotonin reuptake, inhibit norepinephrine reuptake, anticholinergic effects, antihistaminic effects

Question 36

there are multiple less common adverse effects of tricyclic antidepressants include constipation, diarrhea, ataxia, and mydriasis. these are often related to _____ effects

Answer 36

related to anticholinergic effects

Question 37

3 most common adverse effects of tricyclic antidepressants?

Answer 37

sedation, mitosis, urinary retention

Question 38

this tricyclic antidepressant is approved for use in dogs for OCD, dominance aggression, and separation anxiety

Answer 38

clomipramine

Question 39

this atypical antidepressant is a serotonin antagonist and reuptake inhibitor

Answer 39

trazodone