Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology > CNS (only AEDs) > Flashcards

CNS (only AEDs) Flashcards

1
Q

T/F: you don’t need to taper CNS drugs

A

FALSE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Transmission of action potentials between neurons can be electrical or chemical. In the CNS, it is primarily______

A

chemical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the four major classes of neurotransmitters

A
  1. Ach
  2. biogenic amines
  3. amino acids
    4.neuropeptides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the 4 biogenic amines

A

Norepinephrine, dopamine, serotonin, histamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the 3 amino acid NT

A

GABA, glycine, glutamate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the two types of neuropeptide NT

A

substance P
endogenous opiates (enkephalins, endorphins, dynorphins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Excitatory neurotransmitters _______ the likelihood that a neuron will depolarize.
They are often linked to a sodium channel

A

increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Inhibitory neurotransmitters ______the likelihood that a neuron will depolarize.
They are often linked to a chloride channel

A

decrease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

many CNS drugs are only _____ selective for their target

A

relatively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does indirect receptor interaction mediation refer to

A

changing the concentration of a NT, or regulating the receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

With CNS drugs, initial and delayed responses may both be improtant in ultimate clinical effect. What does this mean clinically?

A

you need to be patient with the time to maximal effect of drugs that alter NT concentrations, and you have to taper drugs that affect the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what ability of the drug is critical to its activity in the CNS

A

lipophilicity (how well the drug passes the BBB)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what’s important to remember about active metabolites in CNS drugs

A

they may have a longer half-life than the parent drug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is a seizure

A

the clinical manifestation of the abnormal, excessive, hypersynchronous discharge of a group of neurons within the cerebral cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Seizures start when a group of neurons within the brain becomes

A

hyperexcitable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the goal of antiepileptic therapy in animals with idiopathic epilepsy

A

To balance reduction of seizures with quality of life of the patient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are ALL of the antiepileptic drugs:

A

Phenobarbital
Potassium bromide
Diazepam
levetiracetam
zonisamide
gabapentin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the first choice of AED in vetmed

A

phenobarbital

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Phenobarbital mech of action

A

GABA -A effects increase chloride conductance -> hyperpolarization

GABA- B effects decrease Ca++ influx -> decreased NT release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Phenobarbital is ____ lipophilic

A

moderately. It crosses the BBB but not as rapidly as benzodiazepines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

why do the kinetics of phenobarbital change in the first few days?

A

It undergoes metabolic tolerance due to the induction of cytochrome p450

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is important to remember about the serum concentration of phenobarbital at any specific dose?

A

it is highly variable, due to metabolic tolerance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are type 1 adverse affects of phenobarbital

A

behavioural changes (sedation or hyperexcitability). These are predictable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are type 2 adverse affects of phenobarbital?

A

Immune-mediated anemia/neutropenia and acute hepatotoxicity. These are unpredictable and life threatening

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are type 3 adverse affects of phenobarbital

A

polydipsia and polyphagia, hepatotoxicity, and decreased T4. These are cumulative, and can be potentially life-threatening

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what are type 4 adverse effects of phenobarbital?

A

carcinogenic/teratogenic, though none of htese are reported in dogs.

27
Q

What kind of drugs cause phenobarbital toxicity?

A

Drugs that inhibit cytochrome p450 enzymes (chloramphenicol, cimetidine, ketoconazole)

28
Q

What can induction of cytochrome p450 eznymes by phenobarbital do?

A

change the PK of other drugs (watch out for interactions/adverse effects)

29
Q

WHAT IS SUPER IMPORTANT TO REMEMBER ABOUT THE DOSAGE OF PHENOBARBITAL

A

EFFICACY CORRELATES BETTER WITH SERUM DRUG CONCENTRAION THAN WITH DOSE. SERUM CONCENTRATIONS AT A GIVEN DOSE VARY BETWEEN INDIVIDUALS. THERAPEUTIC DRUG MONITORING IS IMPORTANT, AND DOSE ADJUSTMENTS ARE OFTEN NEEDED. (sorry for yelling)

30
Q

Where is phenobarbital primarily metabolized

A

the liver.

31
Q

75% of phenobarbital is metabolized by the liver into inactive metabolites. Where does the other 25% go?

A

its excreted unchanged by the kidney

32
Q

How to monitor patients on phenobarbital:

A

monitor concentration at first steady state (approx. 2 weeks). Monitor again at clearance time point (6 weeks). Monitor every 6 months if there are 2+ seizure events or 2 weeks after any dose change.

Monitor liver function with serum biochem every 6 months.

33
Q

What is the oldest known treatment for seizures

A

Potassium Bromide (KBr)

34
Q

What is the mech of action of KBr

A

thought to act via GABA Cl- channels to hyperpolarize cells

35
Q

What is the half-life of KBr, and what is the implication?

A

EXTREMELY LONG -> 15 days in dogs, 10 days in cats. This means it is very slow to reach steady state, and loading doses are often used.

36
Q

T/F: KBr undergoes renal clearance with NO hepatic metabolism or protein binding

A

true.

37
Q

When is steady state of KBr reached`

A

at 3 MONTHS!!

38
Q

When should you monitor KBr serum concentrations

A

at 1 and 3 months after starting KBr, then monitor annually, orsooner if evidence of toxicity or ineffectiveness

39
Q

Should you give a higher or lower dose of KBr to animals with kidney disease? Why?

A

You should give a LOWER dose, because KBr undergoes RENAL CLEARANCE and will likely have higher concentrations (the drug isn’t being cleared as effectively, so remains in the blood longer)

40
Q

is Levetiracetam better as a monotherapy, or as an add on for epileptic dogs?

A

an add on.

41
Q

How is Levetiracetam excreted?

A

renal excretion

42
Q

what drug can be useful in addition
to midazolam or diazepam for status epilepticus?

A

Levetiracetam

43
Q

which AED has a short half life and favourable pharmacodynamics that result in a rapid onset of action

A

Levitiracetam

44
Q

Should zonisamide be used as a monotherapy or an add on for epilepsy

A

it can be used for both!

45
Q

Approximately __% of zonisamide is excreted by the kidney.

A

80

46
Q

WHAT MUST YOU TELL OWNERS ABOUT ADMINISTERING ZONISAMIDE

A

THIS IS A HAZARDOUS DRUG THAT CAN CAUSE TERATOGENIC EFFECTS. YOU NEED TO WEAR GLOVES WHEN ADMINISTERING.(sorry for yelling again.)

47
Q

Zonisamide requires a ____ (higher/lower) dose when given with phenobarbital

A

higher.

48
Q

What two AEDs are best for treating acute seizures and managing status epilepticus

A

Diazepam and midazolam (Benzodiazepines)

49
Q

A dog is seizuring in front of you. how do you administer Diazepam

A

IV, per rectum, intranasal

50
Q

a dog is seizuring in front of you. how do you administer midazolam

A

IM, IV, per rectum, intranasal

51
Q

Which can be given IM: diazepam or midazolam

A

midazolam

52
Q

What pharmacodynamic quality allows benzodiazepines to be fast acting

A

they are very lipophilic

53
Q

Diazepam is important for treating:

A

acute seizures and status epilepticus.

54
Q

What can oral diazepam cause in cats?

A

liver necrosis

55
Q

What is the traditionally preferred emergency seizure treatment for dogs>

A

diazepam

56
Q

Why should diazepam not be used for long-term therapy in dogs

A

After IV administration, teh half-life ranges from 15 minutes to three hours. This means it requires too frequent administration, and can lead to tolerance/dependance with chronic use. Also, there is abuse potential by owners.

57
Q

Why is diazepam the preferred emergency seizure treatment?

A

It is more lipophilic than other benzodiazepines, so IV injection rapidly leads to high concentrations in teh CNS

58
Q

How should you advise an owner to stop a seizure?

A

Give them a prescription for Diazepam, and tell them to administer it per rectum during a seizure episode.

59
Q

What is the difference between diazepam and midazolam?

A

Midazolam is similar to diazepam, but is 3 x more potent. Therefore it has a faster onset of action, but a shorter duration of action.

60
Q

How would you advise an owner to stop status epilepticus?

A

give em a prescription for INTRANASAL MIDAZOLAM because a greater percentage of patients achieve cessation of seizure than with rectal diazepam (70% vs 20%)

61
Q

What are the standard treatments for status epilepticus (continuous seizures)

A

IV or rectal diazepam
IV, IM or IN midazolam

62
Q

status epilepticus occurs when a seizure lasts longer than:

A

5-10 minutes

63
Q

Which did the ACVIM deem more potent and safer for status epilepticus: Diazepam or midazolam?

A

Both are safe and potent, but they recommended Midazolam.

Pharmacology (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions