Biomaterial Database

Acute phenytoin toxicity followed by seizure breakthrough from a ticlopidine-phenytoin interaction. 1996

M Privitera, and T E Welty

Department of Neurology, University of Cincinnati College of Medicine, Ohio, USA.

OBJECTIVE To review a case of a drug-drug interaction between phenytoin sodium and ticlopidine hydrochloride that resulted in acute phenytoin toxicity and permanent memory loss. METHODS A 63-year-old man who was maintained with a stable dose of phenytoin for treatment of seizures began treatment with ticlopidine following percutaneous transluminal angioplasty and stent placement. Within 3 weeks of beginning treatment with ticlopidine, he experienced acute clinical toxic effects of phenytoin with a maximum measured phenytoin concentration of 162.4 micromol/L. Phenytoin concentration decreased to 36 micromol/L after discontinuing treatment with ticlopidine and reducing the phenytoin dose. Subsequently, the patient developed probable complex partial status epilepticus. CONCLUSIONS Ticlopidine is a metabolic inhibitor of several drugs. Because of the potential for acute and permanent adverse effects from a drug-drug interaction, phenytoin concentrations should be carefully monitored when beginning or ending ticlopidine therapy.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D010672	Phenytoin	An anticonvulsant that is used to treat a wide variety of seizures. It is also an anti-arrhythmic and a muscle relaxant. The mechanism of therapeutic action is not clear, although several cellular actions have been described including effects on ion channels, active transport, and general membrane stabilization. The mechanism of its muscle relaxant effect appears to involve a reduction in the sensitivity of muscle spindles to stretch. Phenytoin has been proposed for several other therapeutic uses, but its use has been limited by its many adverse effects and interactions with other drugs.	Diphenylhydantoin,Fenitoin,Phenhydan,5,5-Diphenylhydantoin,5,5-diphenylimidazolidine-2,4-dione,Antisacer,Difenin,Dihydan,Dilantin,Epamin,Epanutin,Hydantol,Phenytoin Sodium,Sodium Diphenylhydantoinate,Diphenylhydantoinate, Sodium
D004347	Drug Interactions	The action of a drug that may affect the activity, metabolism, or toxicity of another drug.	Drug Interaction,Interaction, Drug,Interactions, Drug
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013988	Ticlopidine	An effective inhibitor of platelet aggregation commonly used in the placement of STENTS in CORONARY ARTERIES.	53-32C,Ticlid,Ticlodix,Ticlodone,Ticlopidine Hydrochloride,53 32C,5332C,Hydrochloride, Ticlopidine
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D017029	Epilepsy, Complex Partial	A disorder characterized by recurrent partial seizures marked by impairment of cognition. During the seizure the individual may experience a wide variety of psychic phenomenon including formed hallucinations, illusions, deja vu, intense emotional feelings, confusion, and spatial disorientation. Focal motor activity, sensory alterations and AUTOMATISM may also occur. Complex partial seizures often originate from foci in one or both temporal lobes. The etiology may be idiopathic (cryptogenic partial complex epilepsy) or occur as a secondary manifestation of a focal cortical lesion (symptomatic partial complex epilepsy). (From Adams et al., Principles of Neurology, 6th ed, pp317-8)	Complex Partial Epilepsy,Complex Partial Seizure Disorder,Cryptogenic Partial Complex Epilepsy,Disorder, Complex Partial Seizures,Epilepsy, Cryptogenic, Partial Complex,Epilepsy, Psychic Equivalent,Epilepsy, Psychomotor,Epilepsy, Symptomatic, Partial Complex,Partial Complex Epilepsy, Cryptogenic,Partial Complex Epilepsy, Symptomatic,Seizure Disorder, Complex Partial,Symptomatic Partial Complex Epilepsy,Partial Epilepsy, Complex,Psychic Equivalent Epilepsy,Psychomotor Epilepsy