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    Phenytoin (Dilantin) Correction for Albumin / Renal Failure

    Corrects serum phenytoin level for renal failure and/or hypoalbuminemia.


    Use in patients with albumin ≤3.2 g/dL (32 g/L). The “Sheiner-Tozer Equation” is the official name of this correction. This updated formula uses an albumin coefficient of 0.275, and 0.2 for patients with renal failure (see Evidence for details).

    When to Use
    Why Use

    Patients taking phenytoin who have renal failure or albumin ≤3.2 g/dL (32 g/L).

    Phenytoin has a narrow therapeutic window, and is highly protein-bound. The protein-bound phenytoin is what is typically measured by the lab. However, unbound phenytoin is the active portion (it crosses the blood-brain barrier). This calculator helps estimate the equivalent active amount of phenytoin based on typical lab values.

    Helps avoid under- or over-dosing in patients with renal failure or low albumin.



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    Creator Insights
    Dr. Thomas N. Tozer

    About the Creator

    Thomas N. Tozer, PhD, PharmD, BS, is professor emeritus of biopharmaceutical sciences and pharmaceutical chemistry at School of Pharmacy at UCSF. He is the co-author of Clinical Pharmacokinetics and Pharmacodynamics: Concepts and Applications. Prior to retirement, Dr. Tozer researched colon-specific drug delivery, toxicokinetics, kinetics of potential contrast agents for magnetic resonance imaging and nonlinear pharmacokinetics.

    To view Dr. Thomas N. Tozer's publications, visit PubMed

    Are you Dr. Thomas N. Tozer? Send us a message to review your photo and bio, and find out how to submit Creator Insights!
    MDCalc loves calculator creators – researchers who, through intelligent and often complex methods, discover tools that describe scientific facts that can then be applied in practice. These are real scientific discoveries about the nature of the human body, which can be invaluable to physicians taking care of patients.
    Content Contributors
    • Andrew Michalak, MD
    About the Creator
    Dr. Thomas N. Tozer
    Are you Dr. Thomas N. Tozer?
    Content Contributors
    • Andrew Michalak, MD