Phenytoin Intoxication: Burden and risk factors

Area of Science:

• Pharmacology
• Clinical Toxicology
• Hospital Administration

Background:

• Phenytoin is a widely used anticonvulsant medication.
• Adverse drug events, including toxicity, contribute to healthcare costs and patient morbidity.
• Understanding the incidence, causes, and prevention of phenytoin toxicity is crucial for patient safety.

Purpose of the Study:

• To determine the frequency and economic impact of phenytoin toxicity admissions.
• To identify the common clinical manifestations of phenytoin intoxication.
• To elucidate the risk factors and iatrogenic causes of phenytoin toxicity.
• To propose strategies for preventing phenytoin toxicity.

Main Methods:

• Retrospective review of hospital ICD-coded database.
• Analysis of patient admissions for phenytoin toxicity between 1987 and 1998.

Main Results:

• Phenytoin toxicity accounted for 1 in 5,000 hospital admissions, with 31 patients admitted 35 times.
• Common symptoms included ataxia, confusion, dysarthria, and nystagmus.
• Major causes were poor pharmacokinetic awareness, inadequate follow-up, infrequent serum monitoring, and incorrect dosing.

Conclusions:

• Phenytoin intoxication can lead to significant transient morbidity and prolonged hospitalization, though permanent sequelae are rare.
• Preventive measures include enhanced patient education and stepwise dose titration guided by serum drug levels.
• Regular monitoring of phenytoin serum levels, especially after dose changes, is essential to mitigate toxicity risk.