CNS – ANTIEPILEPTIC DRUGS Compare and contrast the terms seizure, convulsion

and epilepsy.

Discuss the indications for antiepileptic therapy (AED).

Compare and contrast the first line drugs of choice for AED.

Discuss the nursing process related to the care of the patient receiving AEDs in acute and chronic situations.

CNS – ANTIEPILEPTIC DRUGSINTERNATIONAL CLASSIFICATION OF

SEIZURES

Partial Seizures – short alterations of consciousness; repetitive unusual movements (chewing or swallowing); psychologic changes; confusion

Simple Seizures – No impaired consciousness; motor symptoms of face, arm or legs; hallucinations of sight, hearing, or taste; tingling sensation; ANS changes; personality changes

Complex Seizures – Impaired consciousness; memory impairment; behavioral effects; purposeless behaviors; aura, unreal feelings, bizarre behavior

Generalized Seizures – Temporary lapses in consciousness; staring off into space; rhythmic movements of eyes, head, or hands; may have tonic, clonic, myoclonic, atonic, or tonic-clonic seizures; brief loss of consciousness without confusion; head drop or falling down symptoms

CNS – ANTIEPILEPTIC DRUGSSYNDROME OF CNS

DYSFUNCTION

Convulsion – Involuntary spasmodic contractions of any or all voluntary muscles throughout the body, including skeletal and facial muscles. Postictal state

Seizures – Brief episode of abnormal electrical activity in the nerve cells of the brain -- detected on EEG

Epilepsy – Chronic, recurrent pattern of seizures

CNS ANTIEPILEPTIC DRUGS /ANTICONVULSANT

DRUGS Terms overlap and are used

interchangeably to achieve the goal of maintaining a reasonable quality of life.

Antiepileptic Drugs: management of all types of epilepsy, not just convulsions (AED Therapy)

Anticonvulsant Drugs: used to prevent the seizures typically associated with epilepsy.

CNS – ANTIEPILEPTIC DRUGSMECHANISM OF ACTION

ION Theory – movement of K+, Na+, Ca+, Mg+:

Stabilizes neurons: from becoming hyperexcited prevents excessive impulses to adjacent neurons

1. Increase threshold of activity in the motor cortex

Makes it more difficult to excite; reduces response

2. Depress the seizure discharge from its origin

Suppress transmission of impulses from one nerve to the next

3. Decrease the speed of nerve impulse conduction within a given neuron

CNS – ANTIEPILEPTIC DRUGSINDICATIONS

Prevention or control of seizure activity Long-term maintenance treatment of epilepsy Acute treatment of convulsions and status

epilepticus Status epilepticus: common seizure disorder –

life-threatening emergency characterized by tonic-clonic convulsions that occur in succession.

Loss of consciousness, hypotension, hypoxia, cardiac dysrhythmias – brain damage and death may quickly result

Once controlled, long term therapy is begun to prevent future seizures

Brain Surgery - Head injuries = prophylactic AED Therapy

CNS – ANTIEPILEPTIC DRUGSCONTRAINDICATIONS

Known drug allergy

Pregnancy – consider risks to mother & infant if untreated

CNS – ANTIEPILEPTIC DRUGSDRUGS OF FIRST CHOICE

AED Therapy Therapeutic Level (mcg/mL)

Adverse Effects

carbamazepine (Tegretol)

3-14 N/V; drowsiness; dizziness; orthostatic hypotension; hypertension; dyspnea; edema; nephrotoxicity; hepatotoxicity; blood dyscrasias; dermatologic reactions

phenytoin (Dilantin)

10-20 Cardiac dysrhythmias; hypotension; N/V indigestion; sedation, drowsiness, dizziness, blurred vision, fatigue, lethargy; confusion; gingival hyperplasia; hyperglycemia; blood dyscrasias; hepatoxicity; dermatologic reactions

primidone (Mysoline)

5-12 Sedation; drowsiness; dizziness; blurred vision; blood dyscrasias; paradoxical excitability

valproic acid (Depakote)

50-100 Drowsiness; N/V; tremor; weight gain; transient hair loss; blood dyscrasias; hepatotoxicity; pancreatitis

CNS – ANTIEPILEPTIC DRUGSTreatment of Status Epilepticus

AED Therapy Dose mg/kg

Onset Adverse Effects

diazepam (Valium)

0.3-0.5

3-10 mins Apnea, hypotension, somnolence

Fosphenytoin (Cerebyx)

15-20 15-30 mins

Cardiac dysrhythmias, hypotension

Lorazepam (Ativan)

0.05-0.1

1-20 mins Apnea, hypotension, somnolence

Phenobarbital 15-20 10-30 mins

Apnea, hypotension, somnolence

Phenytoin (Dilantin)

15-20 5-30 mins Cardiac dysrhythmias, hypotension

CNS – ANTIEPILEPTIC DRUGSBENZODIAZEPINES

Actions Not fully understood May enhance the inhibitory effects of GABA in postsynaptic

clefts between nerve cells Uses

Diazepam (Valium), clonazepam (Klonopin), clorazepate (Tranxene), lorazepam (Ativan) Diazepam - drug of choice for status epilepticus

must be given intravenously -- slowly never mixed with any other medication

Therapeutic outcomes Reduced frequency of seizures, reduced injuries Minimal adverse effects from therapy

CNS – ANTIEPILEPTIC DRUGSHYDANTOINS

Actions – mechanism unknown phenytoin (Dilantin) – most commonly used ethotoin (Peganone) fosphenytoin (Cerebyx)

Uses Anticonvulsants used to control tonic-clonic seizures CAUTION:

Phenytoin must be administered slowly Do not mix with other medications in the same syringe Dilute only with 0.9% NaCl to avoid precipitation Infuse slowly <150mg/min

CAUTION: toxicity may cause nystagmus CAUTION: infiltration causes sloughing of tissue

Therapeutic outcomes Reduced frequency of seizures, reduced injuries Minimal adverse effects from therapy

CNS – ANTIEPILEPTIC DRUGSCARBAMAZEPINE

Actions -- carbamazepine (Tegretol) Blocks up the reuptake of norepinephrine Decreases release of norepinephrine and rate of

dopamine and GABA turnover Mechanisms of action as anticonvulsant are

unknown Uses

Used in combination with other anticonvulsants to control tonic-clonic seizures

Not effective for myoclonic or absence seizures Should not be given with grapefruit – increased

levels of the AED Therapeutic outcomes

Reduced frequency of seizures, reduced injuries Minimal adverse effects from therapy

CNS – ANTIEPILEPTIC DRUGS SUCCINIMIDES

Actions ethosuximide (Zarontin), methsuximide (Celontin)

Mechanism of action unknown

Uses To control absence (petit mal) seizures

Therapeutic outcomes Reduced frequency of seizures, reduced

injuries Minimal adverse effects from therapy

CNS – ANTIEPILEPTIC DRUGS TOPIRAMATE

Actions topiramate (Topomax) Mechanisms of action are unknown May prolong blockade of sodium channels,

enhance activity of GABA, and antagonize certain neurotransmitter receptors

Uses Used in combination with other anticonvulsants

to control tonic-clonic seizures Prevention of migraine headaches

Therapeutic outcomes Reduced frequency of seizures and injuries Minimal adverse effects from therapy

CNS – ANTIEPILEPTIC DRUGS PRIMIDONE

Actions primidone (Mysoline) Metabolized into phenobarbital and PEMA - both

active anticonvulsants Exact anticonvulsant mechanism of action is

unknown

Uses Used in combination with other anticonvulsants

to treat tonic-clonic seizures

Therapeutic outcomes Reduced frequency of seizures and injuries Minimal adverse effects from therapy

CNS – ANTIEPILEPTIC DRUGSGABAPENTIN

Actions gabapentin (Neurontin) Mechanisms of action are unknown Does not appear to enhance GABA

Uses Used in combination with other anticonvulsants

to control partial seizures

Therapeutic outcomes Reduced frequency of seizures Minimal adverse effects from therapy Also used for pain reduction – shingles, peripheral

neuropathy – nerve pain

CNS – ANTIEPILEPTIC DRUGSNURSING IMPLICATIONS

Nurses may play an important role in diagnosis and treatment

Comprehensive history – allergies/medication reconciliation Describe seizures – precipitating events,

duration/frequency, intensity of the seizure activity, postictal behavior – observe & record

Safety – positioning – assist pt during seizure, proper supplies Medication administration guidelines – specific for IV meds

Lab values – check therapeutic blood levels on admission Patient and family support: discuss lifestyle and feelings with

patient

CNS – ANTIEPILEPTIC DRUGSPATIENT EDUCATION

Medication: adherence to prescribe regimen Do not Stop Abruptly – Life Time Treatment - Rebound

Convulsions Medic Alert Bracelet Protective environment Driving – physician prescription/State laws Sedating effects of the drugs – may decrease with time

Avoid alcohol & cigarettes Photosensitivity with certain AEDs – sunscreen &

protective clothing Avoid stimulants Oral hygiene – hyperplasia

CNS – ANTIEPILEPTIC DRUGSREVIEW

When caring for a patient with epilepsy who was hospitalized and successfully treated for status epilepticus, a precaution that the nurse institutes includes:

a. placing oxygen and suction equipment at the bedside. b. assigning an assistant to stay with the patient at all

times. c. keeping an airway available to insert as needed. d. instructing the patient to stay in bed and call for

assistance to go to the bathroom.

CNS – ANTIEPILEPTIC DRUGSREVIEW

A nurse witnesses a patient with a seizure disorder as he suddenly jerks his arms and legs with tonic-clonic type movement, falls to the floor, temporary loss of consciousness, which he regains immediately. The type of seizure demonstrated by this patient and that the nurse documents is:

a. atonic seizure b. myoclonic seizure c. complex partial seizure with automatisms d. generalized seizure