Epilepsy & Anti-seizure Drugs

Question 1

What percentage of epilepsy patients are therapy-resistant?

Answer 1

25-40%

Question 2

What is a seizure?

Answer 2

a finite clinical manifestations of abnormal and excessive excitation of a population of cortical neurons

Question 3

What is epilepsy?

Answer 3

syndrome characterized by chronic, recurrent seizures unprovoked by systemic or neurologic insults

Question 4

What age ranges are most commonly diagnosed with epilepsy?

Answer 4

Pediatric and elderly patients are most likely affected by epilepsy

Question 5

What is the most common inherited etiology of epilepsy?

Answer 5

Faulty ion channels

Question 6

There are partial seizures and generalized seizures. What are the three types of partial seizures?

Answer 6

• Simple partial
• Complex partial
• Secondarily generalized

Question 7

What are the three types of generalized seizures?

Answer 7

• Tonic-clonic (“grand mal”)
• Absence (“petit mal”)
• Atonic (“drop”)

Question 8

What is the difference between a simple partial and complex partial seizure?

Answer 8

A simple partial seizure the person is aware and responsive. Complex partial the person may have memory impairment.

Question 9

Describe a tonic-clonic generalized seizure.

Answer 9

Tonic phase: patient loses control of mind/body and stiffens
Clonic phase: patient jerks limbs
seizure lasts a few minutes

Question 10

How long does the postictal phase last after a grand mal seizure?

Answer 10

minutes to hours

Question 11

Describe a generalized absence seizure.

Answer 11

The patient stares for 2-15 seconds with loss of memory

Question 12

What are some ideal properties of an Anti-Seizure Drug?

Answer 12

wide therapeutic index, long half-life, water soluble

Question 13

When modifying a drug’s therapeutic index, what does a metabolism inhibitor do?

Answer 13

It will inhibit the metabolism/clearance of the drug causing the plasma concentration to near toxicity.

Question 14

When modifying a drug’s therapeutic index, what does a metabolism inducer do?

Answer 14

It will enhance metabolism/clearance of the drug causing the plasma concentration to (lower) near subtherapeutic levels.

Question 15

What are the three main mechanisms for ASDs?

Answer 15

1. Enhancing GABA-mediated inhibition
2. reduction of excitatory transmission (i.e glutamate)
3. modify ionic conductance (i.e. Na, Ca, K)

Question 16

What is Carbamazepine indicated to treat?

Answer 16

Simple & Complex partial seizures; and Tonic-clonic seizures

Question 17

Carbamazepine should be avoided in patients with what type of seizure?

Answer 17

Generalized absence

Question 18

What are common side-effects of carbamazepine?

Answer 18

blurred/double vision, cognitive impairment. (rare: stevens-johnson syndrome)

Question 19

Someone on carbamazepine shouldn’t drink what?

Answer 19

Grapefruit juice - its a metabolism inhibitor

Question 20

What drug is indicated for treating only uncomplicated absence seizures?

Answer 20

Ethosuximide (Zarontin™)

Question 21

What are two special considerations to think about when prescribing Ethosuximide?

Answer 21

• narrow clinical spectrum (absence seizures only)

- very long half life: ~40hr

Question 22

What is Phenytoin (Dilantin™) indicated to treat?

Answer 22

Simple and Complex partial; Tonic-clonic generalized

Question 23

What is one side effect of Phenytoin that we might see in our dental office?

Answer 23

gingival hyperplasia

Question 24

What should Phenytoin never be prescribed to treat?

Answer 24

Absence-type seizures

Question 25

Why should you frequently check plasma concentrations of Phenytoin?

Answer 25

Phenytoin follows zero-order kinetics at high doses (exponential increase in concentration over time)

Question 26

What is Topiramate (Topamax™) indicated to treat?

Answer 26

Simple & Complex partial; Tonic-clonic generalized & Lennox-Gastaut Syndrome

Question 27

What are three common and one uncommon side effects of Topiramate?

Answer 27

common: word recall problems, renal calculi, and weight loss. uncommon: open-angle glaucoma

Question 28

What is Valproic Acid (Depakote™) indicated to treat?

Answer 28

Simple & Complex partial; Absence, atypical Absence, Myoclonic epilepsy, and Tonic-clonic generalized seizures

Question 29

Toxic doses of Valproic Acid will cause what?

Answer 29

Rene-like syndrome and/or hepatic failure

Question 30

What is a common side effect of Valproic acid?

Answer 30

weight gain

Question 31

Patients with what condition should NOT be prescribed Valproic Acid?

Answer 31

hepatic disease or significant hepatic dysfunction

Question 32

Why shouldn’t you give Valproic acid to a pregnant patient?

Answer 32

It increases the risk for neural tube defects like Spina bifida (*Category D risk)

Question 33

If your patient has cirrhosis and experiences Tonic-clonic seizures, what are your drug options?

Answer 33

Phenytoin, Carbamazepine, or Topiramate

Question 34

If your patient has absence-type seizures, what drug(s) could you probably prescribe?

Answer 34

Ethosuximide, or Valproate

Question 35

If your patient has simple partial seizures, what drugs could you possibly prescribe?

Answer 35

Carbamazepine, Phenytoin, Valproate, or Topiramate

Question 36

If your patient has lennox-gastaut syndrome, what drug(s) would you prescribe?

Answer 36

Topiramate

Question 37

Your obese patient suffers from complex partial seizures. What could you prescribe to them to help both problems?

Answer 37

Topiramate (weight loss is common)