Antiseizure Medications Pharmacology Cheat Sheet

Antiseizure medications are used to depress abnormal neuronal discharges and prevent the spread of seizures to adjacent neurons. These should be used with caution in clients taking anticoagulants, acetylsalicylic acid, sulfonamides, cimetidine, and antipsychotic medications.

Absorption is decreased with the use of antacids, calcium preparations, and antineoplastic medications.

Interventions for clients on antiseizure medications:

• Initiate seizure precautions.
• Monitor urinary output.
• Monitor liver and renal function tests and medication blood serum levels.
• Monitor for signs of medication toxicity, which would include CNS depression, ataxia, nausea, vomiting, drowsiness, dizziness, restlessness, and visual disturbances.
• If a seizure occurs, assess seizure activity, including location and duration.
• Protect the client from hazards in the environment during a seizure.

Hydantoins: Fosphenytoin, phenytoin:

• Hydantoins are used to treat partial and generalized tonic-clonic seizures.
• Phenytoin is also used to treat dysrhythmias.

Side and adverse effects of Hydantoins:

• Gingival hyperplasia (reddened gums that bleed easily)
• Slurred speech
• Confusion
• Sedation and drowsiness
• Nausea and vomiting
• Blurred vision and nystagmus
• Headaches
• Blood dyscrasias: Decreased platelet count and decreased white blood cell count
• Elevated blood glucose level
• Alopecia or hirsutism
• Rash or pruritus

Barbiturates: Amobarbital, mephobarbital, Phenobarbital:

Barbiturates are used for tonic-clonic seizures and acute episodes of seizures caused by status epilepticus. Barbiturates also may be used as adjuncts to anesthesia.

Side and adverse effects

• Sedation, ataxia, and dizziness during initial treatment
• Mood changes
• Hypotension
• Respiratory depression
• Tolerance to the medication

Benzodiazepines: Clonazepam, clorazepate, diazepam, lorazepam:

Benzodiazepines are used to treat absence seizures. Diazepam and lorazepam are used to treat status epilepticus, anxiety, and skeletal muscle spasms. Clorazepate is used as adjunctive therapy for partial seizures.

Side and adverse effects
• Sedation, drowsiness, dizziness, blurred vision
• For intravenous injection, administer slowly to prevent bradycardia.
• Medication tolerance and dependency
• Blood dyscrasias: Decreased platelet count and decreased white blood cell count
• Hepatotoxicity

Succinimides: Ethosuximide, methsuximide:

Succinimides are used to treat absence seizures.

Side and adverse effects

• Anorexia, nausea, vomiting
• Blood dyscrasias

Valproates: Valproic acid, divalproex sodium:
Valproates are used to treat tonic-clonic, partial, and myoclonic seizures.

Side and adverse effects
• Transient nausea, vomiting, and indigestion
• Sedation, drowsiness, and dizziness
• Pancreatitis
• Blood dyscrasias: Decreased platelet count and decreased white blood cell count
• Hepatotoxicity


Iminostilbenes are used to treat seizure disorders that have not responded to other anticonvulsants. Iminostilbenes are also used to treat trigeminal neuralgia.

Side and adverse effects
• Drowsiness
• Dizziness
• Nausea and vomiting, dry mouth
• Constipation or diarrhea
• Rash
• Visual abnormalities
• Blood dycrasias, agranulocytosis
• Headache

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