Effect of age, height, weight and sex on serum phenytoin concentration in epileptic patients.

1 Steady-state serum phenytoin concentrations were measured in adult epileptic patients receiving a maintenance dose of phenytoin (300 mg daily). 2 Serum phenytoin concentration showed a positive correlation with age. 3 Serum phenytoin concentration showed a negative correlation with body weight and with height. Multiple correlation analysis indicated that body weight influenced the concentration to a much greater degree than height. 4 When corrected for body weight and height, the serum phenytoin concentrations in women were lower than those in men, although the difference was not statistically significant. 5 Although each of these factors contributes to the interindividual variation in serum phenytoin concentrations, the contribution of each is small. Other factors, such as genetic differences and the effect of saturation kinetics, are much more important in determining steady-state concentrations. Adjusting the dose according to the age, weight and height of a patient would achieve only a marginal improvement in therapy.

[1]  F. Vajda.  Anticonvulsant Therapy: Pharmacological Basis and Practice , 1975 .

[2]  A. J. Robins,et al.  Phenytoin dose adjustment in epileptic patients. , 1974, British journal of clinical pharmacology.

[3]  A. Richens,et al.  Rate of elimination of tracer doses of phenytoin at different steady-state serum phenytoin concentrations in epileptic patients. , 1974, British journal of clinical pharmacology.

[4]  A. Richens,et al.  Phenytoin intoxication induced by sulthiame in epileptic patients , 1974, Journal of neurology, neurosurgery, and psychiatry.

[5]  A. Richens,et al.  Inhibition of phenytoin metabolism by sulthiame in epileptic patients. , 1974, British journal of clinical pharmacology.

[6]  J. M. Shaw,et al.  Pharmacokinetic study of a patient with diphenylhydantoin toxicity , 1973, Clinical pharmacology and therapeutics.

[7]  G. Glaser,et al.  Variation in response to anticonvulsants in a group of epileptic patients. , 1972, Transactions of the American Neurological Association.

[8]  J. Wagner,et al.  Explanation of dose-dependent decline of diphenylhydantoin plasma levels by fitting to the integrated form of the Michaelis-Menten equation. , 1972, Research communications in chemical pathology and pharmacology.

[9]  J. Crooks,et al.  Effect of Age and Sex on Human Drug Metabolism , 1971, British medical journal.

[10]  H. Kutt,et al.  BIOCHEMICAL AND GENETIC FACTORS REGULATING DILANTIN METABOLISM IN MAN * , 1971, Annals of the New York Academy of Sciences.

[11]  I. A. Crump,et al.  Value of blood phenytoin estimation in management of childhood epilepsy. , 1971, Archives of disease in childhood.

[12]  E. Reynolds,et al.  The distribution of plasma phenytoin levels in epileptic patients , 1970, Journal of neurology, neurosurgery, and psychiatry.

[13]  J. Huisman,et al.  Influence of Ethylphenacemide on Serum Levels of Other Anti‐Epileptic Drugs , 1970, Epilepsia.

[14]  N Hurwitz,et al.  Predisposing Factors in Adverse Reactions to Drugs , 1969, British medical journal.

[15]  A. Conney,et al.  Metabolism of drugs and carcinogens by human liver enzymes. , 1966, The Journal of pharmacology and experimental therapeutics.

[16]  F. Buchthal,et al.  DIPHENYLHYDANTOIN AND PHENOBARBITAL. SERUM LEVELS IN CHILDREN. , 1964, American journal of diseases of children.

[17]  B. Brodie,et al.  Species, strain and sex differences in metabolism of hexobarbitone, amidopyrine, antipyrine and aniline , 1958 .

[18]  J. Axelrod.  The enzymatic N-demethylation of narcotic drugs. , 1956, The Journal of pharmacology and experimental therapeutics.

[19]  A. Richens.  Results of a Phenytoin Quality Control Scheme , 1975 .

[20]  M. Eadie,et al.  Diphenylhydantoin dosage. , 1973, Proceedings of the Australian Association of Neurologists.