Phenytoin: the pseudosteady-state phenomenon.
Clin Pharmacol Ther
; 35(6): 822-5, 1984 Jun.
Article
em En
| MEDLINE
| ID: mdl-6734035
ABSTRACT
After reaching an apparent steady state, plasma phenytoin (PHT) levels may then undergo inexplicable changes, a phenomenon called " pseudosteady state". We evaluated 13 pseudosteady -state periods in 10 inpatients with complex partial seizures. Eleven of the periods occurred after a change in PHT dosage and two after drug withdrawal. The pseudosteady -state period began 2 to 12 days (means = 5.7 days) after dosage change and lasted 5 to 10 days (means = 6.3 days), during which plasma PHT levels were stable (+/- 5%). Plasma PHT levels thereafter fluctuated spontaneously by greater than 25% for 5 to 22 days (means = 10.8 days). A final steady-state level was reached 13 to 31 days (means = 21.4 days) after the first dosage change. Falling plasma PHT levels increased seizure frequency in two patients, and a level of 52 micrograms/ml led to medication toxicity in another.
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Base de dados:
MEDLINE
Assunto principal:
Fenitoína
Idioma:
En
Ano de publicação:
1984
Tipo de documento:
Article