title: [Follow-up of a cohort of patients after substitution of phenytoin for phenytoin sodium in an epilepsy center].
abstract: In March 2012, the French Health Products Safety Agency interrupted the commercialization of di-hydan (phenytoin). It was replaced by diphantoïne (phenytoin sodium) and prescribers were informed that posology was equivalent for both products. We conducted a retrospective study of phenytoinemia and clinical effects comparatively for these two drugs in a population of adult patients with epilepsy admitted in La TEPPE. Forty-four patients were included. Mean age was 47.6 years. Phenytoinemia significantly decreased after substitution (17.14mg/L with di-hydan versus 12.17mg/L with diphantoïne, P<8 10(-6)). Moreover an increase in post substitution posology of diphantoïne was noticed (264.77mg/L with di-hydan versus 274.73mg/L with diphantoïne), although not significant (P=0.11). Increase of seizures was non-significant (P = 0.09). The decrease of phenytoinemia was probably due to the difference of composition between the drugs: a 100mg di-hydan tablet contains 100mg of phenytoin whereas a 100mg diphantoïne tablet contains 92mg. The specific non-linear kinetics of phenytoin reinforces this difference. A prospective study could better evaluate the risk of substituting di-hydan with diphantoïne.
authors.affiliation: Cabinet de neurologie, 1, rue Pierre-Rectoran, 64100 Bayonne, France. Electronic address: nolavan70@hotmail.com.
authors.forename: N
authors.initials: N
authors.lastname: Lavandier
authors.affiliation: La Teppe, 25, avenue de la Bouterne, 26602 Tain L'Hermitage cedex, France.
authors.forename: D
authors.initials: D
authors.lastname: Tourniaire
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000927:Anticonvulsants / Q000008:administration & dosage* / Q000737:chemistry; D004304:Dosage Forms; D004305:Dose-Response Relationship, Drug; D057915:Drug Substitution; D004827:Epilepsy / Q000188:drug therapy* / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization; D006782:Hospitals, Special; D006801:Humans; D008297:Male; D008875:Middle Aged; D010672:Phenytoin / Q000008:administration & dosage* / Q000737:chemistry; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D000927:Anticonvulsants; D004304:Dosage Forms; D010672:Phenytoin
keywords: Bioequivalence; Bioéquivalence; Epilepsy; Phenytoin; Phenytoinemia; Phénytoïne; Phénytoïnémie; Substitution; Épilepsie