Phenytoin Dosing Calculator

Patient Name:      Floor:
Age    Weight    Height
Gender      Current albumin level: (g/dl)
What is the current phenytoin level if available? (mcg/ml)
Dosage form used for maintenance dose:
Estimated creatinine clearance:
Read the following:
     -    Program background information


1. Allen JP, Ludden TM, Burrow SR, Clementi WA, Stavchansky SA.  Phenytoin cumulation kinetics.
Clin Pharmacol Ther. 1979 Oct;26(4):445-8.
2.  Bachmann KA, Belloto RJ Jr.  Differential kinetics of phenytoin in elderly patients. Drugs Aging. 1999 Sep;15(3):235-50.
3.  Bauer LA, Blouin RA. Age and phenytoin kinetics in adult epileptics. Clin Pharmacol Ther. 1982 Mar;31(3):301-4.
4.  Burton ME, Vasko MR, Brater DC.  Comparison of drug dosing methods.   Clin Pharmacokinet. 1985 Jan-Feb;10(1):1-37.

5.  Dager WE, Inciardi JF, Howe TL.  Estimating phenytoin concentrations by the Sheiner-Tozer method in adults with pronounced hypoalbuminemia.  Ann Pharmacother. 1995 Jul-Aug;29(7-8):667-70.

6.  Dasgupta A, Dennen DA, Dean R, McLawhon RW. Prediction of free phenytoin levels based on [total phenytoin]/[albumin] ratios. Potential errors with hypoalbuminemia. Am J Clin Pathol. 1991 Feb;95(2):253-6.
7.  Dela Cruz FG, Kanter MZ, Fischer JH, Leikin JB. Efficacy of individualized phenytoin sodium loading doses administered by intravenous infusion. Clin Pharm. 1988 Mar;7(3):219-24.
8.  Flint N, Lopez LM, Robinson JD, Williams C, Salem RB. Related ArticlesComparison of eight phenytoin dosing methods in institutionalized patients.
Ther Drug Monit. 1985;7(1):74-80.
9.  Grasela TH, Sheiner LB, Rambeck B, Boenigk HE, Dunlop A, Mullen PW, Wadsworth J, Richens A, Ishizaki T, Chiba K, et al.  Steady-state pharmacokinetics of phenytoin from routinely collected patient data
10.  Gugler R, Manion CV, Azarnoff DL.  Phenytoin: pharmacokinetics and bioavailability. Clin Pharmacol Ther. 1976 Feb;19(2):135-42.
11.  Hayes MJ, Langman MJ, Short AH.  Changes in drug metabolism with increasing age: 2. phenytoin clearance and protein binding.  Br J Clin Pharmacol. 1975 Feb;2(1):73-9.
12.   Hudson SA, Farquhar DL, Thompson D, Smith RG. Phenytoin dosage individualization--five methods compared in the elderly.  J Clin Pharm Ther. 1990 Feb;15(1):25-34.
13.  Liponi DF, Winter ME, Tozer TN.  Renal function and therapeutic concentrations of phenytoin. Neurology. 1984 Mar;34(3):395-7.
14.  Mabuchi H, Nakahashi H.  A major inhibitor of phenytoin binding to serum protein in uremia. Nephron. 1988;48(4): 310-4.
15.  Martin E, Tozer TN, Sheiner LB, Riegelman S. The clinical pharmacokinetics of phenytoin. J Pharmacokinet Biopharm. 1977 Dec;5(6):579-96.
16.  Martin E, Gambertoglio JG, Adler DS, Tozer TN, Roman LA, Grausz H.  Removal of phenytoin by hemodialysis in uremic patients.  JAMA. 1977 Oct 17;238(16):1750-3.
17.  Mason GD, Winter ME.  Appropriateness of sampling times for therapeutic drug monitoring. Am J Hosp Pharm. 1984 Sep;41(9):1796-801.
18.  Mauro LS, Mauro VF, Bachmann KA, Higgins JT.  Accuracy of two equations in determining normalized phenytoin concentrations.  DICP. 1989 Jan;23(1):64-8.
19.  McCauley DL, Tozer TN, Winter ME.  Time for phenytoin concentration to peak: consequences of first-order and zero-order absorption. Ther Drug Monit. 1989 Sep;11(5):540-2.
20.  Mlynarek ME, Peterson EL, Zarowitz BJ.  Predicting unbound phenytoin concentrations in the critically ill neurosurgical patient. Ann Pharmacother. 1996 Mar;30(3): 219-23.
21.  Peterson GM, Khoo BH, von Witt RJ.  Clinical response in epilepsy in relation to total and free serum levels of phenytoin. Ther Drug Monit. 1991 Sep;13(5):415-9.
22.  Pryka RD, Rodvold KA, Erdman SM. An updated comparison of drug dosing methods. Part I: Phenytoin. Clin Pharmacokinet. 1991 Mar;20(3):209-17.
23.  Sawchuk RJ, Rector TS.  Steady-state plasma concentrations as a function of the absorption rate and dosing interval for drugs exhibiting concentration-dependent clearance: consequences for phenytoin therapy.  J Pharmacokinet Biopharm. 1979 Dec;7(6):543-55.
24.  Sheiner LB, Beal SL.  Evaluation of methods for estimating population pharmacokinetics parameters. I. Michaelis-Menten model: routine clinical pharmacokinetic data.  J Pharmacokinet Biopharm. 1980 Dec;8(6):553-71.
25.  Tozer TN, Winter ME. Phenytoin. In: Evans WE, Schentag JJ, Jusko WJ, eds. Applied Pharmacokinetics: Principles of Therapeutic Drug Monitoring. 3rd Ed. Vancouver, WA: Applied Therapeutics; 1992: 25.1 - 25.44


All calculations must be confirmed before use. The authors make no claims of the accuracy of the information contained herein; and these suggested doses are not a substitute for clinical judgment. Neither GlobalRPh Inc. nor any other party involved in the preparation of this program shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.PLEASE READ THE DISCLAIMER CAREFULLY BEFORE ACCESSING OR USING THIS SITE. BY ACCESSING OR USING THIS SITE, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS SET FORTH IN THE DISCLAIMER.   Read the disclaimer
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