Ch 24 Drugs for Epilepsy

Question 1

Seizures are initiated by discharge from a group of hyperexcitable neurons, called a ___.

Answer 1

focus

Question 2

In partial seizures, excitation undergoes limited spread from the ___.

Answer 2

focus to adjacent cortical areas

Question 3

In generalized seizures, excitation spreads widely throughout ___.

Answer 3

both hemispheres of the brain

Question 4

AEDs act through four basic mechanisms: __(4)__.

Answer 4

blockade of sodium channels,
blockade of calcium channels,
blockade of receptors for glutamate (an excitatory neurotransmitter), and
potentiation of GABA (an inhibitory neurotransmitter)

Question 5

The goal in treating epilepsy is to reduce ____. Complete elimination of seizures may not be possible without causing intolerable side effects.

Answer 5

seizures to an extent that enables the patient to live a normal or near-normal life

Question 6

AEDs can be divided into two main groups: ___

Answer 6

traditional AEDs and newer AEDs.

Question 7

Many AEDs are selective for particular seizure types;

therefore, successful treatment depends on ___.

Answer 7

choosing the correct drug

Question 8

Monitoring plasma drug levels can be valuable for (4), especially in patients taking more than one drug.

Answer 8

adjusting dosage,
monitoring adherence,
determining the cause of lost seizure control, and identifying the cause of toxicity

Question 9

Nonadherence accounts for nearly ___. Promoting adherence is a priority.

Answer 9

half of all treatment failures

Question 10

Withdrawal of AEDs must be done ___.

Answer 10

gradually, because abrupt withdrawal can trigger SE

Question 11

Some AEDs may pose a risk of __ and

behavior.

Answer 11

suicidal thoughts

Question 12

Most AEDs cause CNS depression, which can be deepened by concurrent use of other ___.

Answer 12

CNS depressants (e.g., alcohol, antihistamines, opioids, other AEDs)

Question 13

Phenytoin is active against ___.

Answer 13

partial seizures and tonic-clonic seizures but NOT absence seizures

Question 14

The capacity of the___ is limited. As a result, doses only slightly greater than those needed for therapeutic effects can push phenytoin levels into the toxic range.

Answer 14

liver to metabolize phenytoin

Question 15

The therapeutic range for phenytoin is __.

Answer 15

10 to 20 mcg/mL

Question 16

When phenytoin levels rise above 20 mcg/mL, CNS toxicity develops. Signs include __(5)__.

Answer 16

nystagmus, sedation, ataxia, diplopia, and cognitive impairment

Question 17

Phenytoin causes ___ in 20% of patients

Answer 17

gingival hyperplasia

Question 18

Rarely, phenytoin causes ___. Risk may be increased by the HLA-B*1502 gene variation, seen almost exclusively in patients of Asian descent.

Answer 18

severe skin reactions: 
StevensJohnson syndrome (SJS) or toxic epidermal necrolysis (TEN)

Question 19

Like phenytoin, ___ is active against partial

seizures and tonic-clonic seizures.

Answer 19

carbamazepine

Question 20

Because __ is better tolerated than phenytoin, it is often preferred.

Answer 20

carbamazepine

Question 21

Carbamazepine can cause __(4)__.
To reduce the risk of serious hematologic toxicity, complete blood counts should be obtained at baseline and periodically thereafter.

Answer 21

leukopenia, anemia, and thrombocytopenia—and, very rarely, fatal aplastic anemia

Question 22

Like phenytoin, carbamazepine can cause SJS/TEN. Risk
is clearly increased by the HLA-B*1502 gene variation.
Accordingly, the FDA recommends that ___.

Answer 22

Asian patients should be screened for this variant before using the drug

Question 23

Valproic acid is a broad-spectrum AED, having activity

against ___.

Answer 23

partial seizures and most generalized seizures,
including tonic-clonic, absence, atonic, and myoclonic
seizures

Question 24

Valproic acid can cause potentially fatal ___,
especially in children under 2 years old who are taking
other AEDs.

Answer 24

liver injury

Question 25

Valproic acid can cause potentially fatal __.

Answer 25

pancreatitis

Question 26

___ is highly teratogenic, and can reduce the IQ
of children exposed to it in utero. Accordingly, valproic
acid should not be used during pregnancy, unless it is the only AED that works.

Answer 26

Valproic acid

Question 27

In contrast to other barbiturates, ___ is able to
suppress seizures without causing generalized CNS
depression.

Answer 27

phenobarbital

Question 28

Phenytoin, carbamazepine, and phenobarbital induce the
synthesis of hepatic drug-metabolizing enzymes, and can
thereby accelerate ___.

Answer 28

inactivation of other drugs.

Inactivation of oral contraceptives and warfarin is of particular concern.

Question 29

AEDs can interact with one another in complex ways,

causing their __.

Answer 29

blood levels to change.

Dosages must be adjusted to compensate for these interactions.

Question 30

All traditional AEDs (and some newer AEDs) can harm
the __.
However, the fetus and mother are at greater risk from
uncontrolled seizures than from AEDs. Accordingly, women with major seizure disorders should continue taking AEDs throughout pregnancy.

Answer 30

developing fetus, especially during the first trimester

Question 31

___ can be minimized by avoiding valproic acid and
by using just one AED (if possible) in the lowest effective
dosage.

Answer 31

Fetal risk

Question 32

Initial control of generalized convulsive SE is accomplished with an __.

Answer 32

IV benzodiazepine—either diazepam or lorazepam.

When diazepam is used, follow-up treatment with phenytoin or fosphenytoin is essential for prolonged seizure suppression.