Effect of Drug Therapy on the Metabolism of Phenytoin

  • A. Richens
  • G. W. Houghton


It is common clinical experience that phenytoin is an unpredictable drug to use in practice. Some patients can tolerate doses of 600 mg daily or more without showing signs of drug intoxication, while others become intoxicated with 200 mg or less. On occasion, a patient who has been stabilized for months or years on a constant dose of the drug suddenly develops nystagmus and ataxia. In some patients who are being started on phenytoin therapy, the serum concentration of the drug often remains low despite gradually increasing doses, until suddenly a point is reached when it rises dangerously close to the toxic range with a further increment.


Epileptic Patient Glucaric Acid Phenobarbitone Serum Level Healthy Test Person Phenobarbitone Plasma Level 
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Copyright information

© Springer-Verlag Berlin-Heidelberg 1975

Authors and Affiliations

  • A. Richens
    • 1
  • G. W. Houghton
    • 1
  1. 1.Department of Clinical PharmacologySt. Bartholomew’s HospitalLondonGreat Britain

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