Chapter 23 Antiseizure Agents

Chapter 23  Antiseizure Agents

Complete Chapter Questions And Answers
 

Sample Questions

1.
A patient is admitted to the emergency department with severe recurrent convulsive seizures. What drug would the nurse expect to be ordered for use in emergency control of status epilepticus?
A)
Phenytoin (Dilantin)
B)
Diazepam (Valium)
C)
Phenobarbital (Luminal)
D)
Ethosuximide (Zarontin)
Ans:
C

Feedback:

Phenobarbital is used for emergency control of status epilepticus. This barbiturate inhibits impulse conduction in the ascending reticular activating system (RAS), depresses the cerebral cortex, alters cerebellar function, and depresses motor nerve output. Phenobarbital stabilizes nerve membranes throughout the central nervous system (CNS) directly by influencing ionic channels in the cell membrane, thereby decreasing excitability and hyperexcitability to stimulation. By decreasing conduction through nerve pathways, it reduces the tonic–clonic, muscular, and emotional responses to stimulation. Phenobarbital depresses conduction in the lower brainstem and the cerebral cortex and depresses motor conduction. Phenytoin is used to prevent status epilepticus but is not used to stop seizures after they have started; diazepam is used for short-term treatment of status epilepticus. Ethosuximide is used for absence seizures.

2.
The pharmacology instructor is discussing drugs used for the treatment of partial seizures. What accurately describes the physiological action of carbamazepine?
A)
Reduces electrical activity
B)
Alters sodium and calcium channels
C)
Increases gamma-aminobutyric acid (GABA) activity and blocks sodium and calcium channels to stop action potentials
D)
Depresses conduction in the brainstem and cortex
Ans:
C

Feedback:

Carbamazepine increases GABA activity and blocks sodium and calcium channels to stop action potentials. Succinimides reduce electrical activity. Acetazolamides reduce electrical activity and alter sodium and calcium channels. Barbiturates depress conduction in the brainstem and the cortex.

3.
A 7-year-old girl is brought to the clinic by her mother. The mother states that the child will be engaged in some activity at home and then will just stop for a few seconds and then pick up the activity again as if there had been no break in what she was doing. The nurse suspects the child might be demonstrating what type of seizure?
A)
Tonic–clonic seizure
B)
Absence seizure
C)
Myoclonic seizure
D)
Status epilepticus
Ans:
B

Feedback:

Absence seizures involve abrupt periods of loss of consciousness lasting 3 to 5 seconds. Tonic-clonic seizures involve dramatic muscle contractions, loss of consciousness, and a recovery period characterized by confusion and exhaustion. Myoclonic seizures involve short, sporadic periods of muscle contractions lasting for several minutes. These types of seizures are rare. Status epilepticus seizures are the most dangerous and rapidly occur one after another.

4.
A patient is brought into the emergency department in status epilepticus. The nurse administers phenobarbital 320 mg IV according to protocol. Family members ask the nurse how long it will take to stop the seizures. What is the nurse’s best response?
A)
“The onset of action for the medication is 5 minutes.”
B)
“We should see results in about 10 minutes.”
C)
“It will probably take about 30 minutes before the seizures begin to subside.”
D)
“It may be an hour before the seizures stop.”
Ans:
A

Feedback:

The onset of IV phenobarbital is 5 minutes; however, it is important not to confuse when the onset of action will occur and when the seizures will stop because additional interventions may be needed to stop the seizure activity in some cases. For intramuscular and subcutaneous administration, the onset should be between 10 and 30 minutes. Onset for an oral dose is between 30 and 60 minutes.

5.
The nurse evaluates the patient’s serum phenytoin (Dilantin) level and determines the level is therapeutic when it is within what range?
A)
Between 5 and 12 mcg/mL
B)
Between 10 and 20 mcg/mL
C)
Between 15 and 50 mcg/mL
D)
Between 40 and 100 mcg/mL
Ans:
B

Feedback:

The therapeutic serum level range for phenytoin is between 10 and 20 mcg/mL. The other options are incorrect.