Seizures/Epilepsy Flashcards

1
Q

What is Epilepsy?

A

Chronic Seizure

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2
Q

Classification of Seizures

A

1) Focal (one side of the brain)
2) Generalized (Both sides of the brain)

Tonic - rigid, tense muscles
Clonic - uncontrolled jerking movements

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3
Q

What is a Seizure?

A

This is a sudden, uncontrolled surge of excitatory neuronal activity within the brain.

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4
Q

Causes of seizures?

A

1) Alcohol withdrawal
2) Electrolyte abnormality
3) Fever or infection
4) Head injury
5) Hypoglycemia
6) Drug-induced

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5
Q

What are some drugs which can lower the seizure threshold and cause seizures?

A

1) Opioids (tramadol, meperidine)
2) Antibiotics (Quinolones, Carbapenems, Cephalosporins, Penicillins)
3) Psych (Bupropion, Clozapine, Lithium, TCAs)

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6
Q

Seizure Classification

A

1- Seizures (<5 mins)
2- Status Epilepticus (> 5 mins)

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7
Q

Acute Treatment of Status Epilepticus

A

0-5 mins: Oxygen, monitor labs
5-20 mins: Injectable Benzodiazepines (IV lorazepam, IV diazepam, IM midazolam)
20-40 mins: IV Antisezure Meds (Fosphenytoin, Valproic Acid, Levetiracetam)

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8
Q

Diastat AcuDial Dispensing

A

Pharmacist MUST dial and lock correct prescribed dose.

*This is a rectal diazepam

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9
Q

Chronic Seizure Management

A

Primary Treatment: Lamotrigine, Valproate, Levetiracetam

Adjuvant Treatments: Cannabis-derived products, Neurostimulation, Keto Diet (4:1 ration of fats to combined protein and carb. High-fat, Low-Carb & Protein)

Note: discontinuing any anti-seizure medication abruptly can cause seizures to re-occur. Taper off.

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10
Q

What medications are used to treat Broad Spectrum seizures (Focal and Generalized seizures)?

A

1) Lamotrigine
2) Levetiracetam
3) Topiramate
4) Valproate

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11
Q

What medications are used primarily to treat Focal Seizures?

A

1) Carbamazepine
2) Phenytoin

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12
Q

What medication is primarily used to treat Absense seizures?

A

Ethosuximide

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13
Q

What are the neurotransmitters involved in seizures?

A

1) Glutamate (Excitatory)
2) GABA (Inhibitory)

*Blocking Na channels, decrease excitatory transmission (glutamate)

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14
Q

MOA of Benzodiazepines and Phenobarbital?

A

Enhances GABA effect

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15
Q

MOA of Valproate?

A

Blocks Na channels and increases GABA

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16
Q

MOA of Levetiracetam?

A

Inhibits vesicle fusion by binding SV2A proteins

17
Q

MOA of Carbamazepine, Phenytoin/Fosphenytoin, Topiramate?

A

Blocks Na channels

18
Q

MOA of Ethosuximide?

A

Blocks T-type Ca channels

19
Q

MOA of Lamotrigine?

A

Blocks Na channels and decreases glutamate

20
Q

Common side effects of common ASM?

A

1) CNS Depression (Confusion, sedation, poor coordination, falls)
2) Suicide risk (Changes in mood)
3) Bone loss (increase risk of fractures)
4) Rash (SJS, TEN, DRESS)

SJS - Stevens-Johnson syndrome
TEN - Toxic Epidermal Necrolysis
DRESS - Drug-reaction with Eosinophilia and Systemic Symptoms

21
Q

Lamotrigine

A
  • Also used in Bipolar Disorder

Brand - Lamictal

Boxed Warning - SJS and TEN (both are life threatening) - it is important to report any rash development with Lamotrigine. There is increased risk with higher dosing, dose escalation and valproate use.

Starting dose 25 mg daily. titrate up

Common side effect - Alopecia (supplement with Selenium, Biotin and Zinc)

**IMPORTANT - Monitor for rash and/or fever development. D/c immediately

22
Q

Lamotrigine Starting Kit

A

Orange Kit “Original” - Use if not taking any interacting drug

Blue Kit “Below” - Use if taking Valproate

Green Kit “Grow higher” - Use if taking an enzyme inducer, and would need a higher starting dose

E.g. enzyme inducer - Carbamazepine, Phenobarbital, Phenytoin/fosphenytoin, Primidone

23
Q

Levetiracetam

A

Brand - Keppra

Warnings - Psych based. SJS/TEN

IV:PO - 1:1

*no significant drug interactions

**Preferred in:
1) Infants
2) Pregnancy

24
Q

Topiramate

A

Brand: Topamax

Side Effects: CNS Effects ‘Dopa-max’, weight loss, anorexia

DO not use with oral contraceptives

25
Q

Valproate

A

*Among all of the other anti-seizure medications, valproate has the highest incidence of fetal defects and lower IQ score
Valproate represents all the formulations, including valproic acid

*Side Effects: Somnolence, tremor, weight changes, nausea and vomiting, alopecia

*Hepatic failure can occur

  • Therapeutic Range: 50-100 mcg/mL

Indications: Epilepsy, bipolar, migraine

Valproate can INCREASE levels of Lamotrigine, Phenobarbital, Phenytoin and Warfarin

Carbapenems and estrogen-containing contraceptives can DECREASE levels of Valproate.

26
Q

Lacosamide

A

Brand: Vimpat
Schedule 5 Controlled

Side Effects: Blurred vision, tremor, euphoria

IV:PO is 1:1

27
Q

Carbamazepine & Oxcabazepine

A

CARBAMAZEPINE
Brand of Carbamazepine: Tegretol
Indications: Seizures, Trigeminal neuralgia

Boxed Warning: Stevens-Johnson Syndrome (SJS) [Increased risk for HLA-B*1502)

Contraindications: Myelosuppression

Warning: Fetal harm, hyponatremia (low Na)

Therapeutic Range: 4-12 mcg-mL

Carbamazepine is both a substrate and an inducer for CYP. Therefore it can induce its own metabolism (autoinduction). Oxcarbazepine is not an autoinducer.

Both Carbamazepine and Oxcarbazepine blocks Na channels.

28
Q

Phenytoin

A

Brand: Dilantin
IV:PO is 1:1

Fosphenytoin is a prodrug to Phenytoin
Conversion is 1:1.5. That is 100 mg Phenytoin is 150 mg Fosphenytoin

Boxed Warning: Hypotension and Cardiac Arrythmias with rapid infusion.

Side Effects:
-Acute: Ataxia(poor coordination), Diplopia (double vision), Nystagmus
-Chronic: Gingival hyperplasia, hair growth, hepatotoxicity

29
Q

Phenytoin therapeutic range

A

Total: 10-20 mcg/mL
Free: 1-2 mcg/mL

30
Q

Phenytoin and Fosphenytoin Administration Rate

A

IV Phenytoin: <= 50 mg/min
IV Fosphenytoin: <= 150 mg PE/min

Phenytoin is highly bound to albumin. Therefore patients with low albumin have higher levels of free phenytoin levels.

Corrected Phenytoin = [Total Phenytoin] / [(0.2 x albumin) + 1]
-This is used only in patients with albumin < 3.5 g/dL with CrCl >= 10 mL/min

31
Q

Phenobarbital

A

This is an older medication which enhances GABA.

Schedule 4

-not first line

Warnings: Respiratory Depression, Fetal harm, Drug dependency

Side Effects: Residual sedation, dependence and tolerance. Therefore, do not give to patients with a history of substance abuse.

Primidone is a prodrug for Phenobarbital!

32
Q

Benzodiazepines in Seizures

A

Main ones: Diazepam, Lorazepam, Midazolam, Clobazam

These are used to stop an ACTIVE SEIZURE!

33
Q

Which ASM has therapeutic levels for monitoring?

A

1) Phenytoin
2) Valproate
3) Carbamazepine
4) Phenobarbital

34
Q

ASM Enzyme Inducers

A

1) Carbamazepine and Oxcarbazepine
2) Phenytoin and Fosphenytoin
3) Phenobarbital and Primidone

35
Q

ASM Enzyme Inhibitor

A

1) Valproate

36
Q

ASM in Pregnancy

A

Highest Risk: Valproate
Lowest Risk: Levetiracetam