CNS

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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.

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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

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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

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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.

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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

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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

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CNS Antiepileptic DrugsContraindications

• Known drug allergy
• Pregnancy consider risks to mother infant if
  untreated

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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

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CNS Antiepileptic Drugs
Treatment 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
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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

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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 lt150mg/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

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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

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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

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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

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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

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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

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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

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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

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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.

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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