Comparison of Saliva and Serum Unbound Phenytoin Concentrations in Patients Receiving Phenytoin Monotherapy Versus Concomitant Phenytoin/Valproic Acid.
Abstract number :
2.113
Submission category :
Year :
2000
Submission ID :
516
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Jim M Backes, Masahiro Chiga, Anna Collene, Carrie Williams, Jessica Barnes, Ivan Osorio, Univ of Kansas Medical Ctr, Kansas City, KS.
RATIONALE:To compare the saliva and serum unbound phenytoin (PHT) concentrations in patients receiving PHT monotherapy and PHT/Valproic Acid (VPA) concurrently. METHODS:Phenytoin concentrations of total serum, unbound serum and saliva were collected prospectively in 10 patients receiving phenytoin monotherapy and 2 patients receiving both PHT and VPA. An additional 8 drug concentrations will be obtained in order to have 10 samples in each group. The saliva samples were collected via Oral-Eze?, an oral fluid collection system. All concentrations were determined using flourescence polarization immunoassay. The patients are managed in a comprehensive epilepsy center often requiring high dose, multiple antiepileptic drug therapy. RESULTS:Results from 12 patients (10 receiving PHT monotherapy and 2 receiving PHT/VPA concurrently) indicate the following Concentration Saliva (Cs), Concentration Total (Ct) and Concentration Unbound (Cu) ratios. (See table) CONCLUSIONS: These results demonstrate a reliable correlation between Cs and Cu in patients receiving PHT monotherapy. However, in patients receiving PHT and VPA the correlation between Cs and Cu is less reliable. Additional collection of data will be needed in order to confirm this trend.