Antiepileptic Agents

Antiepileptic Agents

Factors Affecting the Type of Seizure

  • Location of the cells that initiate the electrical discharge
  • Neural pathways that are stimulated by the initial volley of electrical impulses

Classification of Seizures

  • Generalized seizures
    • Begin in one area of the brain and rapidly spread throughout both hemispheres of the brain
  • Partial seizures or focal seizures
    • Begin and remain in one area of the brain

Classification of Generalized Seizures

  • Tonic–clonic seizures (grand mal seizures)
  • Absence seizures (petit mal seizures)
  • Myoclonic seizures
  • Febrile seizures
  • Status epilepticus

Classification of Partial Seizures

  • Simple partial seizures
    • Occur in a single area of the brain and may involve a single muscle movement or sensory alteration
  • Complex partial seizures
    • Involve complex sensory changes
    • Motor changes may include involuntary urination, chewing motions, diarrhea, etc.

Drugs for Treating Tonic–Clonic Seizures

  • Hydantoins
  • Barbiturates
  • Barbiturate-like drugs

Sites of Action of Drugs Used to Treat Various Forms of Epilepsy

Sites of Action of Drugs Used to Treat Various Forms of Epilepsy

Sites of Action of Drugs Used to Treat Various Forms of Epilepsy

 

 

Hydantoins

  • Phenytoin (Dilantin)
    • Treats tonic–clonic seizures and status epilepticus; prevents and treats seizures after neurosurgery
  • Ethotoin (Peganone)
    • Controls tonic–clonic and myoclonic seizures
  • Fosphenytoin (Cerebyx)
    • Controls short-term status epilepticus; prevents seizures after neurosurgery
  • Mephenytoin (Mesantoin)
    • Treats tonic–clonic, myoclonic, and partial (focal) seizures in patients who do not respond to less toxic antiepileptic agents
  • Actions
    • Stabilize nerve membranes and limit the spread of excitability from the initiating focus
  • Indications
    • Treatment of tonic–clonic seizures
  • Pharmacokinetics
    • Well absorbed from the GI tract
    • Metabolized in the liver
    • Excreted in the urine
    • Cerebyx: given IM or IV
  • Contraindications
    • Hepatic or renal impairment at increased risk of toxicity
  • Adverse reactions
    • Nystagmus, ataxia, dysarthria, slurred speech, dizziness, fatigue, headache, dermatitis, and gingival hyperplasia
  • Drug-to-drug interactions
    • Alcohol
    • Wide variety of interactions

Barbiturates and Barbiturate-Like Drugs

  • Phenobarbital (Solfoton, Luminal)
    • Emergency control of status epilepticus and acute seizures; management of tonic–clonic and cortical focal seizures; treatment of simple partial seizures
  • Primidone (Mysoline)
    • Treatment of tonic–clonic or partial seizures
  • Mephobarbital (Mebaral)
    • Treatment of tonic–clonic and absence seizures; anxiolytic/hypnotic agent
  • Actions
    • CNS depressants; inhibit impulse conduction in the ascending RAS
  • Indications
    • Long-term treatment of generalized seizures and emergency control of certain acute convulsive episodes
  • Pharmacokinetics
    • Well absorbed from the GI tract
    • Metabolized in the liver
    • Excreted in the urine
    • T½ varies depending on the agent
    • Can be given IV, IM, or sub-q depending on the agent
  • Contraindications
    • Known allergy
  • Adverse reactions
    • Somnolence, insomnia, vertigo, hallucinations, and anxiety
  • Drug-to-drug interactions
    • Wide variety of interactions

Benzodiazepines

  • Diazepam (Valium)
  • Prototype benzodiazepine
  • Useful in relieving tension, anxiety, and muscle spasm
  • Clonazepam (Klonopin)
  • Used for the treatment of absence (petit mal) seizures and myoclonic seizures
  • Actions
    • Potentiate the effects of GABA, an inhibitory neurotransmitter that stabilizes nerve cell membranes
  • Indications
    • Management of anxiety disorders and acute alcohol withdrawal; muscle relaxant; adjunct in status epilepticus and severe recurrent
  • seizures
  • Pharmacokinetics
    • Well absorbed from the GI tract
    • Metabolized in the liver and excreted in the urine
    • T½ depends on the drug
  • Contraindications
    • Known allergy
  • Adverse reactions
    • Drowsiness, sedation, depression, lethargy, fatigue, disorientation, and urinary retention
  • Drug-to-drug interactions
    • Wide variety of interactions

Succinimides

  • Ethosuximide (Zarontin)
    • Drug of choice for treating absence seizures
    • Relatively few adverse effects compared with many other antiepileptic drugs
  • Methsuximide (Celontin)
    • Used to treat absence seizures that are resistant to other drugs
    • Associated with bone marrow suppression
  • Actions
    • Modulate the inhibitory neurotransmitter GABA
    • Suppress the abnormal activity in the brain
  • Indications
    • Absence seizures or petit mal seizures
  • Pharmacokinetics
    • Absorbed from the GI tract
    • Peak in 1 to 7 hours
    • Metabolized in the liver and excreted in the urine
    • Crosses the placenta and enters the breast milk
  • Contraindications
    • Known allergy
  • Cautions
    • Renal or hepatic disease
  • Adverse reactions
    • Depression, drowsiness, fatigue, ataxia, insomnia, headache, and blurred vision
  • Drug-to-drug interactions
    • Primidone

Other Drugs for Treating Absence Seizures

  • Valproic acid (Depakene)
    • Reduces abnormal electrical activity in the brain; may increase GABA activity at inhibitory receptors
  • Acetazolamide (Diamox)
    • A sulfonamide drug especially effective for treatment of absence seizures in children
  • Zonisamide (Zonegran)
    • Used as an adjunct to other drugs for the treatment of absence seizures

Drugs for Treating Partial Seizures

  • Action
    • Stabilize nerve membranes
      • Altering sodium and calcium channels
      • Increasing the activity of GABA
  • Indication
    • Treatment of partial seizures
  • Pharmacokinetics
    • Absorbed from the GI tract
    • Metabolized in the liver and excreted in the urine and feces
  • Contraindications
    • Known allergy, bone marrow suppression, and hepatic dysfunction
  • Cautions
    • Pregnancy, lactation, and renal stones
  • Adverse reactions
    • Drowsiness, fatigue, weakness, confusion, nausea, vomiting, and anorexia
  • Drug to-drug interactions
    • CNS depressants
    • Numerous interactions

Use of Antiepileptic Agents Across the Lifespan

Use of Antiepileptic Agents Across the Lifespan

Use of Antiepileptic Agents Across the Lifespan

 

 

Prototype Hydantoins

Prototype Hydantoins

Prototype Hydantoins

 

 

Prototype Barbiturates and Barbiturate-Like Drugs

Prototype Barbiturates and Barbiturate-Like Drugs

Prototype Barbiturates and Barbiturate-Like Drugs

 

 

Prototype Benzodiazepines

Prototype Benzodiazepines

Prototype Benzodiazepines

 

 

Prototype Succinimides

Prototype Succinimides

Prototype Succinimides

 

 

Prototype Drugs for Treating Partial Seizures

Prototype Drugs for Treating Partial Seizures

Prototype Drugs for Treating Partial Seizures

 

 

Nursing Considerations for Hydantoins

  • Assessment (history and physical exam)
  • Nursing diagnosis
  • Implementation
  • Evaluation

Nursing Considerations for Succinimides

  • Assessment (history and physical exam)
  • Nursing diagnosis
  • Implementation
  • Evaluation

Nursing Considerations for Drugs for Treating Partial Seizures

  • Assessment (history and physical exam)
  • Nursing diagnosis
  • Implementation
  • Evaluation
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