Unit 3-Antiepileptics Flashcards Preview

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Flashcards in Unit 3-Antiepileptics Deck (52):
1

Phenytoin

Drug class

Voltage-gated Na channel stabilizer

2

Phenytoin

Mechanism

Stabilize inactive conformation of Na channel

 

3

Phenytoin

Uses

Less effective for absence (particular pediatric), myoclonic, atonic seizures

IV route useful for status epilepticus

4

Phenytoin

Side effects

  • Rash, gingival hyperplasia, hirsutism, lupus-like reaction;
  • can cause contraceptive failure
  • Mild myelosuppression, increased LFT;
  • long-term: cerebellar degeneration, peripheral neuropathy, osteoporosis
  • IV infusion limited by hypotension;
  • hepatic enzyme inducer (both auto- and hetero-inducer), highly protein bound

5

Carbamazepine

Drug class

Voltage-gated Na channel stabilizer

6

Carbamazepine

Mechanism

Stabilize inactive conformation of Na channel

7

Carbamazepine

Uses

  • More effective for complex partial seizure than primary generalized;
  • bipolar disorder;
  • neuropathic pain

8

Carbamazepine

Side effects

  • Rash (rarely, Stevens-Johnson), mild myelosuppression, mild increase in LFTs;
  • can cause contraceptive failure
  • Hepatic enzyme inducer (both auto- and hetero-inducer); highly protein bound; must increase dose in 1-2 wks due to autoinduction; side effects likely due to epoxide metabolite

9

Oxcarbamazepine

Drug class

Voltage-gated Na channel stabilizer

10

Oxcarbamazepine

Mechanism

Stabilize inactive conformation of Na channel

11

Oxcarbamazepine

Uses

  • More effective for complex partial seizure than primary generalized;
  • bipolar disorder;
  • neuropathic pain

12

Oxcarbamazepine

Side effects

  • Rash (rarely, Stevens-Johnson), mild myelosuppression, mild increase in LFTs;
  • can cause contraceptive failure
  • Designed to bypass carbamazepine epoxide;
  • less protein-bound, less autoinduction, fewer interactions, less toxic, longer half-life than carbamazepine

13

Lamotrigine

Drug class

Voltage-gated Na channel stabilizer

14

Lamotrigine

Mechanism

Stabilize inactive conformation of Na channel

15

Lamotrigine

Uses

  • Primary generalized epilepsies, absence seizures;
  • indicated in children;
  • bipolar disorder;
  • neuropathic pain

16

Lamotrigine

Side effects

  • Rash, (rarely, Stevens-Johnson):
  • slow initial titration important;
  • may lead to contraceptive failure
  • May exacerbate myoclonic seizures;
  • competes with valproic acid for excretion (potential synergy);
  • hepatic enzyme inducer;
  • not very protein bound

17

Valproate

Mechanism

Unknown; likely affects Na-gated channels and GABA system

18

Valproate

Uses

  • Broad spectrum: absence, myoclonic, tonic-clonic, primary generalized, partial onset, and secondary generalized seizures (but not absence seizures);
  • IV for status epilepticus;
  • bipolar treatment, migraine and long-term cluster headache prophylaxis

19

Valproate

Side effects

Weight gain, hair turnover, hyperammonemia (which can be mitigated with oral carnitine), teratogenicity, blood dyscrasias

Pancreatitis

20

Vigabatrin

Drug class

GABAergic anti-epileptic

21

Vigabatrin

Mechanism

GABA transaminase binder (slows down intracellular breakdown of GABA)

Works on GABA-A

22

Vigabatrin

Uses

Anti-epileptic

23

Tigabine

Drug class

GABAergic anti-epileptic

24

Tigabine

Mechanism

GABA reuptake inhibitor

Works on GABA-A

25

Tigabine

Uses

Anti-epileptic

26

Benzodiazapines

Uses

GABAergic anti-epileptic

27

Benzodiazapines

Mechanism

Bind GABA-A

28

Benzodiazapines

Uses

Status epilepticus (refractory); anesthesia

29

Benzodiazapines

Side effects

Sedation

Long-term usefulness limited by tolerance

30

Gabapentin

Drug class

GABA analog

31

Gabapentin

Mechanism

Block presynaptic influx of Ca

32

Gabapentin

Uses

  • Adjunct for partial complex epilepsy;
  • more commonly used for neuropathic pain

33

Gabapentin

Side effects

Sedation

Absorption limited by intestinal AA transporter (there is a Tm); limited protein binding; no metabolism or drug interaction in humans (so few side effects)

34

Pregabalin

Drug class

GABA analog

35

Pregabalin

Mechanism

Block presynaptic influx of Ca

36

Pregabalin

Uses

  • Adjunct for partial complex epilepsy;
  • more commonly used for neuropathic pain

37

Topiramate

Drug class

Glutamate Receptor Blockers

38

Topiramate

Mechanism

  • Partial AMPA, Kainate Ca receptor blocker
  • secondary effect at voltage-gated Na channel, GABA system

39

Topiramate

Uses

  • Partial onset seizures, secondary generalized seizures, primary generalized epilepsy;
  • migraine prevention, long-term prevention of cluster headaches

40

Topiramate

Side effects

Mild metabolic acidosis, kidney stones (due to some carbonic anhydrase activity); modest weight loss; rare acute glaucoma; sedation

Word-finding problems

Carbonic anhydrase activity leads to mild metabolic acidosis, which leads to respiratory compensation, which leads to mild alkalosis, which leads to calcium ionization, which leads to tingling; treat with vitamin C (acidify urine)

41

Felbamate

Drug class

Glutamate Receptor Blockers

42

Felbamate

Mechanism

NMDA receptor blocker; secondary effect at voltage-gated Na and Ca channels, GABA system

43

Felbamate

Uses

Partial onset seizures with or without secondary generalization; medically refractory epilepsy

44

Felbamate

Side effects

Uncommon but potentially fatal. Aplastic anemia, acute hepatic failure. Requires monitoring.

45

Levetiracetem

Drug class

Synaptic vesicle binder

46

Levetiracetem

Mechanism

Binds synaptic vesicle protein 2, leading to less NT release

47

Levetiracetem

Uses

Partial onset seizures, secondary generalized seizures; maybe primary generalized epilepsy

48

Levetiracetem

Side effects

Well tolerated; sedation, mostly; rarely, irritability, aphasia, thrombocytopenia

49

Ethosuximide

Drug class

Voltage-gated Ca channel blocker

50

Ethosuximide

Mechanism

Blocks T-type Ca-channels in thalamo-cortical circuits

Readily absorbed, minimal first pass metabolism; not protein bound

51

Ethosuximide

Uses

Absence seizures only (and neuropathic pain)

52

Ethosuximide

Side effects

Nausea (transient), sedation, irritability