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Plasma Diphenylhydantoin Levels in Australian Adults
Author(s) -
Hooper W. D.,
Tyrer J. H.,
Eadie M. J.
Publication year - 1974
Publication title -
australian and new zealand journal of medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.596
H-Index - 70
eISSN - 1445-5994
pISSN - 0004-8291
DOI - 10.1111/j.1445-5994.1974.tb03216.x
Subject(s) - dose , body weight , medicine , drug , plasma levels , therapeutic index , plasma concentration , pharmacokinetics , drug metabolism , endocrinology , physiology , pharmacology
Summary: The effects of body weight, sex, concurrent therapy and dosage increment on the correlation between diphenylhydantoin plasma level and dose were studied in 229 adults. The correlation between plasma level and dose was improved by expressing the latter on a body weight basis rather than as a total daily dose without regard to body weight. Sex did not influence the correlation but the intake of other drugs did. There was considerable variation between patients in the diphenylhydantoin dose (on a body weight basis) needed to raise plasma drug level from zero to 5–10 μ g/ml, but when plasma drug levels were above the latter range, a given dose increment (on a body weight basis) had a more uniform effect on drug plasma level in different patients. It is suggested that diphenylhydantoin metabolism varies rather considerably from patient to patient, but that as metabolism approaches saturation (i.e. at drug plasma levels over 7 μ g/ml) the drug tends to accumulate rather uniformly in the body in relation to the patient's body weight. Knowledge of these relationships can assist in the determination of appropriate diphenylhydantoin dosages for patients.