EXAM #3: ANTICONVULSANTS

Question 1

What causes a seizure?

Answer 1

Abnormally excessive, synchronous, and rhythmic firing of populations of hyper-excitable neurons

Question 2

What is epilepsy?

Answer 2

Chronic neurological disorder characterized by recurrent seizures

Question 3

What is the general feature of partial seizures?

Answer 3

Only part of the brain is involved i.e. seizure stars in one region and remain there

Question 4

What is the general feature of a generalized seizure?

Answer 4

Involvement of the entire brain with global EEG changes

Question 5

What are the three subtypes of partial seizures?

Answer 5

1) Simple Partial
2) Complex Partial
3) Partial becoming generalized

Question 6

What is a Simple Partial Seizure?

Answer 6

• Seizure with no loss of consciousness and only focal involvement
• Characterized by minimal spread of abnormal neuronal discharge

Question 7

What is a Complex Partial Seizure?

Answer 7

• Seizure with altered consciousness and potential automatisms
• Focus originates in a small brain area and quickly spreads to other areas

Question 8

What is a partial seizure becoming generalized?

Answer 8

Partial seizure that spreads throughout the brain and progresses to a generalizes seizure

Question 9

What is the most common type of partial seizure?

Answer 9

Complex partial

Question 10

What is an automatism?

Answer 10

Lip smacking
Fumbling
Swallowing

Question 11

What is an Absence or Petit Mal seizure?

Answer 11

• Brief LOC with some motor signs/ automatisms

- Typically seen in children

Question 12

What is a Tonic-Clonic or Grand Mal seizure?

Answer 12

Prototypical seizure with tonic spasms and major convulsions with LOC

Question 13

What are the stages of seizures?

Answer 13

1) Aura
2) Tonic phase–rigidity
3) Clonic phase–convulsions
4) Stuporous state/sleep

Question 14

What is Status Epilepticus?

Answer 14

• Continuous or very rapidly recurring seizures (tonic-clonic)
• Medical EMERGENCY

Question 15

What is an atonic seizure?

Answer 15

Sudden loss of muscle/ postural tone

Question 16

What are the three stages of epileptic seizure generation?

Answer 16

1) Initiation i.e. lowered threshold of activation
2) Synchronization of surrounding tissue
3) Propagation and recruitment of normal neurons

Question 17

What is an EPSP?

Answer 17

Excitatory Postsynaptic Potential

Question 18

What is the molecular basis for EPSPs?

Answer 18

Na+ influx
Ca++ currents
Paroxysmal Deplarization

Question 19

What is the goal of antiepileptic medications?

Answer 19

Restoration of normal patterns of electrical activity

Question 20

What are the three drugs that are best to treat partial seizures?

Answer 20

Carbamazepine
Phenytoin
Valrpoate

Question 21

What are the drugs that are best to treat tonic clonic seizures?

Answer 21

Carbamazepine
Phenytoin
Valrpoate

Question 22

What drugs are best for treating absence/petite mal seizures? What ion channel do these drugs block?

Answer 22

Ethosiximide
Valproate

Ca++*

Question 23

What drugs are best for treating myoclonic seizures?

Answer 23

Clonazepam

Valproate

Question 24

What drugs are best for treating status epilepticus?

Answer 24

Diazepam
Lorazepam
Phenytoin
Fosphenytoin

Question 25

What is the general mechanism of action of anticonvulsant drugs?

Answer 25

Inhibit firing of hyperexctiable cerebral neurons

Question 26

How do anticonvulsants inhibit firing of hyperexcitable neurons?

Answer 26

1) Decrease excitatory effects of glutamate by blocking voltage-gated Na+ channels 2) Increase inhibitory effects of GABA 3) Alter neuronal activation by altering Ca++ currents i.e. block voltage gated Ca++ channels (T-type)

Question 27

What do Na+ blockers do in treating seizures?

Answer 27

Bind to the Na+ channel in inactive state and prevent conversion back to resting state *****This decreases sustained, high frequency, and repetitive discharge****

Question 28

What is the effect of reducing Ca++ influx in the pre-synaptic neuron?

Answer 28

Decreased NT release

Question 29

What type of seizures are Ca++ blockers best at treating?

Answer 29

Petit mal

Question 30

What are the side effects of anticonvulsant drugs?

Answer 30

- Sedation - Diplopia - Nystagmus - Ataxia - GI upset

Question 31

What can happen with the abrupt withdrawal of anticonvulsants?

Answer 31

Increased potential for seizures

Question 32

What are the special considerations regarding anticonvulsants and women?

Answer 32

1) Decreases efficacy of oral contraceptives | 2) Teratrogenic

Question 33

What anticonvulsant is considered to be the safest in pregnancy?

Answer 33

Phenobarbital