Anticonvulsants

Question 1

What are the general guidelines for epileptic drug use?

Answer 1

Monotherapy, don’t suddenly withdraw or start with a high dose, watch out for side effects, toxicity and individual variation

Question 2

What anticonvulsant would be used for postherpetic neuralgia?

Answer 2

Gabapentin, lidocaine, pregabalin

Question 3

What anticonvulsant would be used for diabetic neuropathy?

Answer 3

Carbamazepine, duloxetine, phenytoin, gabapentin, lamotrigine, pregabalin

Question 4

What anticonvulsant would be used for HIV neuropathy and central post-stroke pain?

Answer 4

Lamotrigine

Question 5

What anticonvulsant would be used for trigeminal neuralgia?

Answer 5

Carbamazepine, lamotrigine, oxcarbazepine

Question 6

What is the best medication to use for focal onset seizures?

Answer 6

Carbamazepine, phenytoin

Question 7

What is the best meds to use for general onset (tonic-clonic) seizures?

Answer 7

Valproate, topiramate

Question 8

What is the mechanism of action for carbamazepinem, valproate, lamotrigine and phenytoin?

Answer 8

Inactivation of the sodium channel intracellularly

Question 9

What are the general characteristics for phenytoin?

Answer 9

Oldest nonsedative, fosphenytoin (prodrug) better use for parenternal use, alters Na, Ca2+, K+, inhibits high frequency repetitive firing

Question 10

What is the toxicity to phenytoin?

Answer 10

Ataxia, nystagmus, cognitive impairment, gingival hyperplasia, coarsing of facial features, exacerbates absence seizures, decerebrate rigidity

Question 11

What are the therapeutic uses for carbamazepine?

Answer 11

All partial seizures, highly effective for tonic-clonic

Question 12

What are some features of crabamzepine?

Answer 12

Binds to adenosine receptors, inhibits uptake of NE (not GABA) potentiate postsynaptic effects of GABA, metabolite active

Question 13

What is the toxicity to carbamazepine?

Answer 13

Granulocyte suppression, aplastic anemia, exacerbates absence seizures

Question 14

What are the features of oxcarbazepine?

Answer 14

Active metabolite, first choice for partial and generalized as adjunct

Question 15

What is the toxicity to oxcarbazepine?

Answer 15

Hyponatremia, less hypersensitive of induction of hepatic enzymes

Question 16

What are the features of lamotrigine?

Answer 16

Add for for valproic acid, T1/2=24 hrs, blocks Na channel firing

Question 17

What is lamotrigine used for?

Answer 17

Myoclonic, atonic and generalized seizures in childhood + absence attacks

Question 18

What is the toxicity for lamotrigine?

Answer 18

Life threatening rash “Steven Johnson”

Question 19

What are the features of levetiractam?

Answer 19

Broad spectrum, binds to synpatic vesicular protein SV2A, modifies release of GABA and glutamate

Question 20

What is levetiractam used for?

Answer 20

Myoclonic, atonic, generalized seizures in childhood and atypical absence

Question 21

What are the side effects of levetiracetam?

Answer 21

Somnolence, ataxia, anxiety, agitation, dec RBC

Question 22

What is phenobarbital used for?

Answer 22

50% favorable response to simple partials

Recurrent tonic-clonic

Question 23

What is the toxicity for phenobarbital?

Answer 23

Sedation, cognition impairment

CAN WORSEN absence and atonic seizures

Question 24

What are the features of phenobarbital?

Answer 24

Blocks GLU (AMPA), prolongs opening of Cl channels

Question 25

What are the features of ezogabine?

Answer 25

Adjunct therapy for partial seizures and refractory partial epilepsy in pts First AED to target open voltage-gated K channels Enhances GABA

Question 26

What are the side effects of ezogabine?

Answer 26

Urinary retention, somnolence, dizziness, confusion

Question 27

What are the features of gabapentin?

Answer 27

Adjunct in partial and generalized tonic-clonic | Analog of GABA, dec neuronal Ca currents by binding of a-2-delta subunits

Question 28

What are the features of topiramate?

Answer 28

Rapidly absorbed, T1/2=20-30 hrs Blocks firing of neurons and Na channels Potentiates GABA, depress action of kainate on AMPA

Question 29

What is the toxicity of topiramate?

Answer 29

Weakness carbonic anhydrase inhibitor, paresthesias, teratogenic

Question 30

What are the features of tiagabine?

Answer 30

Nipecotic acid, t1/2 = 5-8 hrs. adjunctive therapy, GABA uptake inhibitor to glial cells Partial seizures

Question 31

What is the toxicity of tiagabine?

Answer 31

Ab pain w/ nausea, tremor, psychosis, skin rash

Question 32

What are the features of zonisamide?

Answer 32

Sulfanmide, T1/2 = 1-3 days Tonic-clonic seizures Inactivation of Na channels, bind GABA

Question 33

What is the toxicity of zonisamide?

Answer 33

Anorexia, renal stones, metabolized by CYP3A4