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Nova Southeastern University

Ron and Kathy Assaf College of Nursing

NUR 3161: Fundamentals of Pharmacology

Antiepileptic Drugs

Epilepsy

• (^) Seizure
  • (^) Brief episode of abnormal electrical activity in nerve cells of the brain
• (^) Convulsion
  • (^) Involuntary spasmodic contractions of any or all voluntary muscles throughout the body, including skeletal, facial, and ocular muscles
• (^) Epilepsy
  • (^) Chronic, recurrent pattern of seizures

Epilepsy (cont’d)

Status Epilepticus

• (^) Multiple seizures occur

with no recovery

between them

• (^) Result:
  • (^) Hypotension
  • (^) Hypoxia
  • (^) Brain damage
  • (^) Death
• (^) True medical

emergency

• (^) Also known as anticonvulsants
• (^) Goals of therapy
  • (^) To control or prevent seizures while maintaining a reasonable quality of life
  • (^) To minimize adverse effects and drug-induced toxicity
• (^) AED therapy is usually lifelong
• (^) Combination of drugs may be used Antiepileptic Drugs (AEDs)

• (^) Single-drug therapy started before multiple-drug

therapy is tried

• (^) Serum drug concentrations must be measured
  • (^) Therapeutic drug monitoring
  • (^) Serum concentrations of phenytoin, phenobarbital, carbamazepine, levetiracetam, and primidone correlate better with seizure control and toxicity than do those of valproic acid, ethosuximide, and clonazepam Antiepileptic Drugs (cont’d)

• (^) Exact mechanism of action is unknown
• (^) Pharmacologic effects
  • (^) Reduce nerve’s ability to be stimulated
  • (^) Suppress transmission of impulses from one nerve to the next
  • (^) Decrease speed of nerve impulse conduction within a neuron
• (^) Indications
  • (^) Prevention or control of seizure activity
  • (^) Long-term maintenance therapy for chronic, recurring seizures
  • (^) Acute treatment of convulsions and status epilepticus Antiepileptic Drugs (cont’d)

• (^) Numerous adverse effects—vary per drug
• (^) Adverse effects often necessitate a change in

medication

• (^) Black box warning as of 2008
  • (^) Suicidal thoughts and behavior Antiepileptic Drugs: Adverse Effects

Barbiturates

• (^) Mechanism of Action
  • (^) Stabilize nerve membranes throughout the central nervous system (CNS) directly by influencing ionic channels in the cell membrane, thereby decreasing excitability and hyperexcitability to stimulation
  • (^) Absorbed from the gastrointestinal (GI) tract, metabolized in the liver, and excreted in the urine
  • (^) This drug has very low lipid solubility, giving it a slow onset and a very long duration of activity
• (^) Examples
  • (^) Phenobarbital (Luminol, Solfoton)
  • (^) Primidone (Mysoline)

Barbiturates (cont’d)

• (^) Indications: long-term treatment of generalized

tonic-clonic and cortical focal seizures, emergency

control of certain acute convulsive episodes (status

epilepticus, tetanus, eclampsia, meningitis)

• (^) Contraindications: known allergy, porphyria, liver or

kidney impairment, and respiratory illness

• (^) Adverse effects: cardiovascular (CV), CNS, GI, and

dermatologic reactions

• (^) Most common adverse effect: sedation
• (^) Therapeutic range: serum drug levels 10 to 40

μg/mL

Benzodiazepines (cont’d)

• (^) Indications: anxiety disorders, acute alcohol

withdrawal, muscle relaxant, tetanus, adjunct in

status epilepticus and severe recurrent convulsive

seizures

• (^) Contraindications: drug allergy, impaired renal or

liver function, depression or psychoses

• (^) Use caution with older adult or debilitated clients
• (^) Interactions: alcohol

Benzodiazepines (cont’d)

• (^) Adverse effects:

drowsiness, sedation,

depression, lethargy,

apathy, fatigue,

disorientation,

bradycardia, tachycardia,

paradoxical excitatory

reactions, constipation,

diarrhea, incontinence,

urinary retention, drug

dependence with

withdrawal syndrome

Hydantoins (cont’d)

• (^) Indications: tonic-clonic and psychomotor seizures,

prevention of seizures during pregnancy, prevention

of seizures during neurosurgery, control of status

epilepticus

• (^) Contraindications: drug allergy, impaired renal or

liver function, depression or psychoses

• (^) Use caution with older adult or debilitated clients
• (^) Interactions: alcohol

Hydantoins (cont’d)

• (^) Adverse effects: gingival hyperplasia, acne, hirsutism, Dilantin facies, and osteoporosis - (^) Occurs more frequently with long-term therapy - (^) Others: nystagmus, ataxia, dysarthria, slurred speech, mental confusion, dizziness, fatigue, tremor, headache (HA), dermatitis, Stevens-Johnson syndrome, nausea, liver damage, and hematopoietic complication
• (^) Therapeutic levels are usually 10-20 μg/mL