Valproic acid hepatic fatalities. III. U.S. experience since 1986

Area of Science:

• Pharmacovigilance
• Hepatology
• Clinical Toxicology

Background:

• Valproic acid (VPA) is a widely prescribed anticonvulsant and mood-stabilizing drug.
• Hepatotoxicity is a known, albeit rare, severe adverse effect of VPA therapy.
• Previous studies have indicated a risk of fatal hepatotoxicity associated with VPA.

Purpose of the Study:

• To conduct a third retrospective study on the U.S. experience with fatal hepatotoxicity linked to valproic acid (VPA).
• To identify the incidence, clinical presentation, and risk factors for fatal VPA-induced hepatotoxicity.

Main Methods:

• Retrospective analysis of U.S. patient data from 1987 to 1993.
• Inclusion criteria focused on patients who developed fatal hepatotoxicity while on VPA therapy.
• Data collection included patient demographics, VPA usage, clinical signs, and risk factors.

Main Results:

• Over one million patients received new VPA prescriptions between 1987 and 1993.
• Twenty-nine cases of fatal hepatotoxicity associated with VPA were identified.
• Common signs included decreased alertness, jaundice, vomiting, hemorrhage, increased seizures, anorexia, and edema.
• Identified risk factors: young age (especially <2 years), polytherapy, developmental delay, and metabolic disorders.
• The highest risk group was patients under 2 years old on polytherapy (1:600).

Conclusions:

• Fatal hepatotoxicity due to VPA is a serious concern, particularly in specific patient populations.
• Young children (<2 years) on polytherapy are at a significantly elevated risk.
• Awareness of these risk factors is crucial for monitoring and managing VPA therapy to prevent severe outcomes.