Generic Name

Ethotoin

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Classification

FDA Approved Indications

• Epilepsy, particularly for focal seizures

Mechanism of Action

Ethotoin stabilizes neuronal membranes by inhibiting voltage-gated sodium channels, thereby reducing repetitive neuronal firing and seizure propagation.

Dosage and Administration

Adult: Initially 200 mg 2-3 times daily, titrating up based on response and tolerability.

Pediatric: Typically 10-15 mg/kg/day divided into 2-3 doses, titrated gradually.

Geriatric: Start at the lower end of dosing range; monitor closely due to potential sensitivity.

Renal Impairment: Dose adjustment may be necessary; consult specific guidelines.

Hepatic Impairment: Use with caution; no specific adjustment specified.

Pharmacokinetics

Absorption: Well absorbed from gastrointestinal tract.

Distribution: Extensive, protein-bound (~80%).

Metabolism: Primarily hepatic via oxidation.

Excretion: Urine mainly as metabolites; small amount as unchanged drug.

Half Life: Approximately 8-20 hours.

Contraindications

• Hypersensitivity to ethotoin or other hydantoins.
• History of hepatic disease.

Precautions

• Use cautiously in patients with hepatic impairment, hematologic abnormalities, or history of blood dyscrasias. Regular blood counts recommended.

Adverse Reactions - Common

• Drowsiness, dizziness (Common)
• Nausea, vomiting (Uncommon)

Adverse Reactions - Serious

• Blood dyscrasias (aplastic anemia, leukopenia, thrombocytopenia) (Rare)
• Hepatotoxicity (Rare)
• Stevens-Johnson syndrome (Very rare)

Drug-Drug Interactions

• Other CNS depressants, phenytoin, phenobarbital, carbamazepine, valproic acid.
• Drugs altering hepatic enzymes.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed.
• Report signs of blood dyscrasias: easy bruising, bleeding, sore throat, fever.
• Avoid alcohol and CNS depressants.
• Report signs of hepatic dysfunction: jaundice, abdominal pain.

Special Considerations

Black Box Warnings:

• Potential for serious blood dyscrasias and hepatotoxicity.

Genetic Factors: None well-established.

Lab Test Interference: May interfere with certain lab tests (e.g., blood counts).

Overdose Management

Signs/Symptoms: Drowsiness, ataxia, nystagmus, CNS depression.

Treatment: Supportive care, activated charcoal if recent ingestion, hemodialysis in severe cases.

Storage and Handling

Storage: Store at room temperature, protected from light and moisture.

Stability: Stable for 2-3 years under proper storage conditions.