3 - Anti-Epileptic Drugs Flashcards

1
Q

Seizure Defined

A

Transient altercation of behavior due to the disorderd, synchronous and rhythmic of brain neurons; sustained depolarization

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2
Q

Epilepsy Defined

A

Disorder of brain function characterized by the periodic and unpredictable occurrence of seizures

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3
Q

Epilepsy Classification/Generalized Seizures: Generalized Tonic Clonic (Both Hemispheres/Grand Mal): Tonic Phase (4)

A

Incontinence

Epileptic Cry

Cyanosis

Generalized stiffening of body and limbs, back arched

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4
Q

Epilepsy Classification/Generalized Seizures: Generalized Tonic Clonic (Both Hemispheres/Grand Mal): Clonic Phase (4)

A

Cyanosis

Eyes Blinking

Salivary Frothing

Clinic jerks of limbs, body and head

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5
Q

Epilepsy Classification/Generalized Seizures: Generalized Tonic Clonic (Grand Mal): Post-Ictal Confusional Fatigue (1)

A

Limbs and body limp

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6
Q

Epilepsy Classification/Generalized Seizures: Absence Seizures Defined (2)

A

Between seizures patient is normal

During Seizure: vacant stare, eyes roll up, eyelids flutter (3/seconds), cessation of activity, lack of response ; LOC

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7
Q

Epilepsy Classification/Generalized Seizures: Other (2)

A

Myoclonic Seizures –> shock like jerk of a group of muscle, no LOC

Atonic Seizures –> NO LOC

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8
Q

Partial Seizures: Simple Partial Seizures Defined

A

Originate from a single cortical side/single hemisphere

NO LOC, stiffening or jerking movements of limp

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9
Q

Partial Seizures: Complex Partial Seizures (Temporal Lobe Epilepsy/Psychomotor Seizures)

A

Originates in temporal lobe and involves limbic system

Hallucinations, aura signaling onset, autamatism (purposeless actions)

Localized onset, can involve both hemisphere

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10
Q

Partial Seizures: Partial with Secondarily Generalized (1)

A

Begins focally from a single cortical side and can become generalized

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11
Q

Epileptic Drugs: Phenobarbitone MOA (2)

A

Potentiation of synaptic inhibition through an action on GABA-A receptor; prolongs DURATION of channel opening events

Enhances GABA receptor mediated current by prolonging the opening of Cl- channels

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12
Q

Epileptic Drugs: Phenobarbitone At Higher Levels - MOA

A

Limits sustained repetitive firing of neurons through an action on Na+ conductance

Inhibits Ca2+ currents

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13
Q

Epileptic Drugs: Phenobarbitone Toxicity (5)

A

Sedation, initially

Nystagmus and Ataxia

Rashes

Megaloblastic anemia (long term use, interference with folic acid metabolism)

Osteomalacia (Vitamin D and K metabolism enhanced)

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14
Q

Epileptic Drugs: Phenobarbitone Use (4)

A

Generalized Tonic Clonic

Simple Partial

Complex Partial

3rd line drug for Status Epilepticus (IM/IV)

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15
Q

Epileptic Drugs: Phenytoin Mechanism (2)

A

Limits the sustained high frequency repetitive firing of action potentials

Slows the rate of recovery of voltage activated Na+ channels from inactivation (channels are inactivated for longer time)

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16
Q

Epileptic Drugs: Phenytoin Pharmacokinetics Low Doses (1) High Doses (1) and Implication (1)

A

Low doses: metabolism is capacity limited, follows first order kinetics (saturation kinetics; as you increase the dose, the metabolism also keeps up)

High doses: follows zero order kinetics (metabolism gets saturated, can’t keep up with increasing disease)

Implies that small increase may lead to disproportionate plasma levels; shifts kinetics

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17
Q

Epileptic Drugs: Phenytoin Adverse Affects at Therapeutic Levels (10-20 mcg/ml) (6)

A

Gum atrophy

Hirsutism (long term use)

Hypersensitivity Reactions (rashes, DLE, LAD)

Fetal Hydantoin Syndrome (contraindicated in pregnancy) –> cleft lip, etc.

Megaloblastic Anemia

Osteomalacia

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18
Q

Epileptic Drugs: Phenytoin Adverse Affects at High Plasma Levels (2, second about nystagmus)

A

Cerebellar and Vestibular Manifestations: Ataxia, Vertigo, Diplopia, and Nystagmus

Nystagmus occurs early, sign that plasma concentrations exceeding therapeutic levels)

19
Q

Epileptic Drugs: Phenytoin Drug Interactions (1)

A

Induce microsomal enzymes responsible for the metabolism of a number of drugs

20
Q

Epileptic Drugs: Phenytoin Uses (4)

A

GTC (first line drug)

Simple and Complex Seizures (first line drug)

Status Epileptics (second line drug)

Trigeminal Neuralgia

21
Q

Epileptic Drugs: Carbamazepine MOA (1)

A

Inhibits high frequency repetitive firing by prolonging the inactivated state of Na+ channels

Same as Phenytoin

22
Q

Epileptic Drugs: Carbamazepine Adverse Effects (6)

A

Vertigo

Diplopia

Ataxa

Drowsiness (higher doses ONLY)

Hyponatremia and water intoxication (SIADH)

Agranulocytosis –> rarely, but patient dependent

23
Q

Epileptic Drugs: Carbamazepine Use (5)

A
  • Most Effective for complex partial seizures, with psychotic symptoms*
  • GTC and SPS –>FIRST CHOICE DRUG*

Neuralgias (Neurosyphilis, Tabes Dorsalis)

Manic-Depressive

Acute Mania

24
Q

Epileptic Drugs: Carbamazepine - Oxcarbazepine (3)

A

Less potent

Shorter acting

Better toxicity profile –> less likely to cause agranulocytosis

25
Q

Epileptic Drugs: Ethosuximide MOA (3)

A

Primary site of action on THALAMOCORTICAL system

Selectively inhibits low threshold, high amplitude T(ransient) type Ca2+ current; impulses die down

EEG: 3 per second spike and wave pattern (absence seizures)

26
Q

Epileptic Drugs: Ethosuximide Toxicity (4)

A

Gastric: Pain, Nausea and Vomiting

Lethargy and fatigue

Hypersensitivity (rashes, DLE)

27
Q

Epileptic Drugs: Ethosuximide Use (1)

A

Absence seizure ONLY

28
Q

Epileptic Drugs: *Valproic Acid/Sodium Valproate MOA (3)

A

Inhibits sustained repetitive firing (like phenytoin)

Reduces low threshold T type Ca2+ current (like ethosuximide)

Increases levels of GABA (like phenobarbitone)

29
Q

Epileptic Drugs: Valproic Acid/Sodium Valproate Toxicity (A lot)

A

Transient GI: Anorexia, Nausea, and Vomiting

Alopecia, hair curling, rashes, appetite stimulation

*Fulminant hepatitis below the age of 2, can be fatal

Neural tube defects in pregnancy (Spina Bifida, Anencephaly, and Encephalocele)

30
Q

Epileptic Drugs: Valproic Acid/Sodium Valproate Uses (4 with pairs)

A

Absence seizure

Alternative/adjuvant - GTC, SPS, CPS

Myoclonic and atonic seizures

MDP and mania

31
Q

Epileptic Drugs: IV Diazepam (2)

A

Emergency control of convulsions: e.g. status epilepticua, tetanus, eclampsia

Can cause sedation

32
Q

Epileptic Drugs: Clonazepam (2)

A

Used in absence seizures and some cases of myoclonic seizsures and infantile spasms (West Syndrome; childhood epileptic syndrome)

Sedation is prominent

33
Q

Epileptic Drugs: Gabapentin/Pregabalin (5)

A

Add on drugs, not used alone

2 DIFFERENT drugs, but SAME MOA

Analogs of GABA (amino acid)

Add on - partial and GTC

Also used in neuropathic pain

34
Q

Epileptic Drugs: Lamotrigine (4)

A

Blocks Na+ channels and prevents the release of excitatory neurotransmitters (glutamate)

Add on - refractory cases of partial and secondarily generalized

Skin rash can occur (Steven-Johnson Syndrome)

35
Q

Epileptic Drugs: Vigabatrin (3)

A

Inhibitor of GABA transaminase

Add on-refractory cases of partial seizsures

*Visual disturbances may develop** –> tunnel vision and bluish vision

36
Q

Epileptic Drugs: Tiagabine (2)

A

Inhibitor of GABA UPTAKE

Adjuvant in partial seizures

37
Q

Epileptic Drugs: Zonisamide (2)

A

Acts on Sodium Channel (like phenytoin)

Partial and GTC

38
Q

Epileptic Drugs: Levetiracetam (1)

A

Partical Seizures

39
Q

Epileptic Drugs: Topiramate (5)

A

Blocks repetitive firing

GTC and partial

Migraine

Can cause kidney stones

Lennox Gestaut Syndrome –> childhood epileptic syndrome

40
Q

See Slide 29 For

A

Table

41
Q

Epileptic Drugs: Felbamate MOA (1)

A

Blocks NMDA receptor

42
Q

Epileptic Drugs: Felbamate Adverse Effects (2)

A

Aplastic Anemia

Severe Hepatitis

43
Q

Epileptic Drugs: Felbamate Use (1)

A

Third-line drug for refractory cases of partial seizures