Neuro: Clinical Flashcards

1
Q

ACVIM 2015 recommendations on when to start AEDs

A
  1. Known cause: Structural disease is present or prior brain injury is known.
  2. Acute severe seizures: Status epilepticus (>5 minutes duration or >3 seizures within 24 hours)
  3. Chronic seizures: >2 seizures within 6 months
  4. Severe post-ictal period
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2
Q

ACVIM 2015 recommendations for AEDs that may be used as mono therapy (order of preference)

A
  1. Phenobarbital, Imepitoin, 2. KBr
  2. Zonisamide, levetiracetam
  3. Primidone
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3
Q

ACVIM 2015 recommendations for AEDs that may be used as add on therapy (order of preference)

A
  1. Phenobarbital, levetiracetam, KBr, Zonisamide
  2. Imepitoin
  3. Primidone
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4
Q

Phenobarbital: MoA

A

Enhance the effectiveness of the GABAa receptor.

May also inhibits release of other neurotransmitters such as Act, nEP and glutamate.

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5
Q

KBr MoA

A

Bromide competes with chloride transport thus resulting in membrane hyperpolarisation.

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6
Q

Primidone MoA

A

85% is metabolised to phenobarbital

No benefit to using this over phenobarbital.

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7
Q

Imepitoin MoA

A

Partial agonist of the BNZ receptor of GABAa receptor.

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8
Q

Levetiracetam MoA

A

Largely unknown but may bind to SV2A which is a presynaptic protein

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9
Q

Zonisamide

A

May reduce sodium and T-type calcium channel opening on the post-synapse of excitatory neurons

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10
Q

When might trough sampling of phenobarbital be useful?

A

When patients seizure close to the next scheduled dose of the drug.

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11
Q

When should phenobarbital monitoring be performed following a start/change in therapy?

A

2w (steady state concentration)
6w (steady state of clearance - d/t liver enzyme induction)
then q6m and 2w after dose changes

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12
Q

When should KBr monitoring be performed

A
  • 6-12 weeks
  • annual basis
  • if >3 seizures occur before next evaluation
  • signs of toxicity
  • perform >2 hours post dosing
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13
Q

What consideration should be made regarding dosing of levetiracetam when using this alongside phenobarbital?

A

May need higher doses due to phenobarbitals metabolic effects.

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14
Q

Which enzyme metabolises Zonisamide?

A

CYP3A4

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15
Q

Which AED drugs are affected by phenobarbital administration?

A

Levetiracetam and zonisamide

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16
Q

TDM recommendations for zonisamide

A
  • 1-2 weeks following initiation or dose adjustment
  • if a change in seizure frequency occurs
  • evaluation of both peak and trough is recommended
17
Q

AED that may result in idiosyncratic blood dyscrasias?

A

Phenobarbital (immune mediated)

18
Q

AED that may result in pancreatitis?

A

KBr

19
Q

AED resulting in GI irritation

A

KBr

20
Q

AED that may result in idiosyncratic renal and hepatic disease

A

Zonisamide (causes RTA)

21
Q

AED that may result in superficial necrolytic dermatitis

A

Phenobarbital

22
Q

How is KBr toxicity treated?

A

Saline diuresis which will enhance renal excretion

23
Q

What diagnostic test results can be affected by Zonisamide?

A

Thyroid - may result in reduction of TT4. (fT4 and TSH should remain normal)

24
Q

Which of the following dietary strategies may be effective in reducing seizure frequency in dogs:

  • MCT
  • Omega-3 supplementation
  • Ketogenic diet
A

MCT diet

Ketogenic diet is helpful in humans.