Biomaterial Database

A graphical nomogram method for predicting toxic concentrations of unbound phenytoin. 1994

J Pospisil, and D Pelclová

Department of Clinical Pharmacology, Charles University of Prague, Czech Republic.

The graphical nomogram method to estimate the phenytoin free concentration at any selected total serum phenytoin and/or albumin concentrations was applied using Scatchard binding equation. The binding parameters were calculated by the non-linear least-squares regression analysis of the binding data collected from 96 outpatients on common anticonvulsant therapy. Free phenytoin concentration was measured by the Amicon multi-micro ultrafiltration system. The mean values of N and Kapp were found to be: N = 1.03, and Kapp = 18,500 (M-1). Correlation coefficient for relationship between measured and predicted free phenytoin concentrations was very good (r = 0.94), but the results of prediction-error analysis (MPE = 0.153, and RMSE = 0.296) show that the nomogram method overpredicts the measured free phenytoin (PHT) concentration approximately about 10% higher (15-30 mg/l) than serum phenytoin levels.

UI	MeSH Term	Description	Entries
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
D011237	Predictive Value of Tests	In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.	Negative Predictive Value,Positive Predictive Value,Predictive Value Of Test,Predictive Values Of Tests,Negative Predictive Values,Positive Predictive Values,Predictive Value, Negative,Predictive Value, Positive
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D012709	Serum Albumin	A major protein in the BLOOD. It is important in maintaining the colloidal osmotic pressure and transporting large organic molecules.	Plasma Albumin,Albumin, Serum
D062787	Drug Overdose	Accidental or deliberate use of a medication or street drug in excess of normal dosage.	Drug Overdoses,Overdose, Drug,Overdoses, Drug