Anticonvulsants Flashcards

1
Q

True or false: All epileptic episodes are accompanied by convulsions.

A

False. Not all, but majority. Some just involve loss of consciousness

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2
Q

What is the difference between primary and secondar epilepsy? Which is more common? How does treatment duration for each differ?

A

Primary (70%) - No specific cause. chronic drug treatment

Secondary (30%) - Known cause for seizure (e.g. stroke, illness), treat till underlying cause is gone

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3
Q

What are the 2 types of partial seizures?

A

Simple

Complex

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4
Q

What are the 5 types of generalized seizures?

A
Tonic Clonic
Absence 
Myoclonic
Febrile Seizures
Status Epilepticus
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5
Q

Partial epilepsy originates from _ within the cortex. If the electrical activity spreads throughout the cortex, then you have a _

A

Small group of neurons (seizure focus)

Generalized tonic clonic seizure

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6
Q

A seizure characterized by no impairment of consciousness, non-spreading focal motor, sensory, autonomic or psychic disturbances is a _

A

Simple Partial seizure

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7
Q

A seizure characterized by impaired consciousness, dream-like state with/without automated movement and electrical activity that can spread through out the cortex is _

A

Complex partial seizure

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8
Q

A seizure that spreads through out both hemispheres of the brain, accompanied by immediate loss of consciousness and may or may not be convulsive is a _

A

Generalized seizure

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9
Q

A seizure characterized by a period of rigid extension of trunk and limbs accompanied by a loss of consciousness, followed by a period of rhythmic contraction of limbs is a _. This is also known as _

A

Tonic clonic seizure

Grand mal

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10
Q

A seizure characterized by a brief loss of consciousness, patient staring followed by rapid eye blinking, usually in patients aged 3 - puberty is a _. This is also known as _

A

Absence seizure

Petit mal

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11
Q

A seizure characterized by short episodes of muscle contractions that may reoccur over several minutes is _. The major cause of this type of seizure is _

A

Myoclonic

Permanent neurological damage

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12
Q

A seizure characterized by tonic clonic convulsions in young (up to 5 years) feverish children is _

A

Febrile seizures

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13
Q

A seizure characterized by repeated seizures without recovery of consciousness between them, with seizures lasting up to 30 minutes is _.

A

Status epilepticus

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14
Q

A type of seizure characterized as a medical emergency and carries risk of cardiovascular collapse and permanent brain damage is _

A

Status epilepticus

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15
Q

Would you expect more/less blood flow to an area of the brain involved with the onset of a seizure?

A

More blood flow

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16
Q

Three main objectives of antiepileptic drugs are _

A

Block origin of seizure activity
Block spread
Block syncronization of neuronal activity

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17
Q

4 antiepileptic drugs that work by inhibiting voltage gated sodium channels, thus extending the refractory period of neurons are _

A

Carbamazepine
Phenytoin
Lamotrigine
Valproic acid

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18
Q

2 antiepileptic drugs that work by inhibiting voltage gated calcium channels, thus inhibiting rhythmic activity of neurons are _

A

Ethosuxamide

Valproic acid

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19
Q

2 classes of antiepileptic drugs that enhance GABAergic inhibitory neurotransmission are _. What 2 other “individual” drugs have the same effect?

A

Benzodiazepine
Barbiturates
Valproic acid
Gabapentin

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20
Q

What type of calcium channels are responsible for the rhythmic firing activity of neurons and are thus the targets of valproic acid and ethosuxamide?

A

T-type calcium channels

21
Q

What is the way to treat status epilepticus?

A
  • Begin IV rapid acting antiepileptics (e.g. diazepam)
  • support CV and repiratory function
  • Follow with IV long acting antiepileptic (e.g. phenytoin)
22
Q

What is the drug of choice for treating epilepsy in adult? What types of seizures is it good for? What types of seizures is it not good for?

A

Phenytoin
Good - Partial simple, partial complex, tonic clonic
Bad - Absence

23
Q

What is the mechanism by which phenytoin works?

A

Blocks voltage gated sodium channels, blocks repeated firing

24
Q

Under what conditions is phenytoin administered orally? IV? Does it bind plasma proteins? What are the 2 CYP enzymes that metabolize it? What is a prodrug for phenytoin that is used IM and IV?

A

Orally (chronic), IV (emergency)
Binds highly (90%) to plasma proteins
CYP2C9 and CYP2C19
Fosphenytoin

25
Q

Phenytoin increases the metabolism of what other 2 drugs? What drug stimulates phenytoin’s metabolism? What 2 inhibit phenytoin metabolism?

A

Doxycycline and cyclosporine
Carbamazepine
Chloramphenicol and Sulfonamide

26
Q

In addition to phenytoin, what is another drug of choice for simple partial, simple complex and tonic clonic seizures? What is the mechanism

A

Carbamazepine

Blocks voltage gated sodium channels, blocks action potential propagation

27
Q

While slowly absorbed orally, why is carbamazepine able to rapidly penetrate the brain? What is unique about its interaction with CYP450 enzymes?

A

Highly lipid soluble

Induces its own metabolism with chronic use

28
Q

In addition to its own metabolism, what other drug’s metabolism does carbamazepine enhance?

A

Phenytoin

29
Q

What is the drug of choice for myoclonic seizures? How does it work? (3)

A

Valproic acid

Blocks Na, Ca and facilitates GABA transmission

30
Q

What is a drug that combines sodium valproate and valproic acid? What is the reason for this combination?

A

Divalproex

Improves GI tolerance

31
Q

What is the drug of choice for treating absence seizures? What is the mechanism?

A

Ethosuximide

Blocks T-type calcium channels, reduces rhythmicity

32
Q

Regarding ethosuxamide, how well does it bind plasma proteins? What percentage is excreted unchanged in urine? What percentage is metabolized by CYP enzymes?

A

Doesn’t bind plasma proteins
25 percent excreted unchanges
75 percent metabolized

33
Q

What barbiturates are used to treat seizures (2)? What are the 3 types of seizures they are used to treat? How can you acheive dose sparing with these barbiturates?

A

Phenobarbital, Primidone
Febrile, Tonic clonic, Simple Partial
Combine with carbamazepine or phenytoin

34
Q

What is the metabolic product of primidone? What is the effect / mechanism of barbiturates?

A

Phenobarbital

Increase GABA inhibitory transmission

35
Q

What is the drug class of choice for the treatment of status epilepticus? What are 2 examples provided? What other types of seizure can be treated with this drug (2)? What is a drawback of long term use?

A

Benzodiazepines
Diazepam and lorazepam
Myoclonic and absence seizures
Tolerance develops in 1-6 months

36
Q

In addition to phenytoin and carbamazepine, what is a newer type of drug used to treat simple partial, complex partial and tonic clonic seizures? What is the mechanism?

A

Lamotrigine

Suppresses glutamate release, prevents Na+ firing

37
Q

Regarding lamotrigine, what antiepileptic drugs decrease its half life? Increase its half life?

A

Decrease - Phenytoin and carbamazepine

Increase - Valproic acid

38
Q

Besides lamotrigine, what is another new type of drug used to treat simple partial, complex partial and tonic clonic seizures? What is the mechanism?

A

Gabapentin

Blocks Ca++ channels, blocks glutamate release

39
Q

What is unique about gabapentine metabolism? Does it bind plasma proteins? What drugs does it interact with?

A

It is not metabolized, excreted by kidneys
No plasma protein binding
No drug interactions

40
Q

What types of seizures is topiramate used to treat? How does it work?

A

simple partial, complex partial and tonic clonic seizures

Blocks Na+ channels, increases postsynaptic GABA-A activity

41
Q

What types if seizures is pregabalin used to treat? How does it work? This mechanism is similar to what other newer antiepileptic?

A

Blocks Ca++ channels, blocks glutamate release

Gabapentin

42
Q

What drug is considered an adjunct for the treatment of simple partial, complex partial and tonic clonic seizures? How does it work?

A

Levetiracetam

Binds synaptic SV2A, modifying GABA and glutamate release

43
Q

What are 5 common side effects of antiepileptics?

A
Drowsiness/sedation
Ataxia
Nausea/vomiting
Skin rash
Metabolic changes
44
Q

An antiepileptic associated with gingival hyperplasia, megaloblastic anemia, and teratogenic effects is _

A

Phenytoin

45
Q

An antiepileptic associated with hepatotoxicity, thrombocytopenia, and teratogenic effects is _

A

Valproic acid

46
Q

An antiepileptic associated with hepatotoxicity and teratogenic effects is _

A

Carbamazepine

47
Q

An antiepileptic associated with megaloblastic anemia alone is _

A

Primidone

48
Q

An antiepileptic associated with thrombocytopenia alone is _

A

Pregabalin

49
Q

An antiepileptic associated with teratogenic effects alone is _

A

Phenobarbital