TY - JOUR
T1 - Urine and plasma free phenytoin concentration correlation
AU - Canto, Daniel T.
AU - Ludden, Thomas M.
AU - Bertoni, John M.
AU - Littlefield, Louis C.
AU - Sagraves, Rosalie A.
AU - Mackey, Ray W.
PY - 1982/11
Y1 - 1982/11
N2 - In an attempt to find a simple, noninvasive method for estimating the plasma free concentration (Cpf) of phenytoin (PHT), the relationship between urine PHT concentration (Cu) and Cpf was studied in 40 epileptic patients who were 6 to 50 yr old. Cu was determined by gas-liquid chromatography and Cpfby equilibrium dialysis at 37°. Cu was generally greater than Cpf, but correlation between the two was strong (r2 = 0.876) and in the same range as previously published results for saliva and Cpf. Correlation of Cu with Cpf was not influenced by patient age, urine pH, or urine flow rate. In 24 patients timed urine collections were obtained and calculated renal clearances of PHT were shown to increase in proportion to urine flow rates. Although it is not known if renal impairment and albuminuria will alter the relationship between Cu and Cpf, it appears that Cu may be useful in estimating the concentration of pharmacologically active PHT in plasma.
AB - In an attempt to find a simple, noninvasive method for estimating the plasma free concentration (Cpf) of phenytoin (PHT), the relationship between urine PHT concentration (Cu) and Cpf was studied in 40 epileptic patients who were 6 to 50 yr old. Cu was determined by gas-liquid chromatography and Cpfby equilibrium dialysis at 37°. Cu was generally greater than Cpf, but correlation between the two was strong (r2 = 0.876) and in the same range as previously published results for saliva and Cpf. Correlation of Cu with Cpf was not influenced by patient age, urine pH, or urine flow rate. In 24 patients timed urine collections were obtained and calculated renal clearances of PHT were shown to increase in proportion to urine flow rates. Although it is not known if renal impairment and albuminuria will alter the relationship between Cu and Cpf, it appears that Cu may be useful in estimating the concentration of pharmacologically active PHT in plasma.
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U2 - 10.1038/clpt.1982.213
DO - 10.1038/clpt.1982.213
M3 - Article
C2 - 7128003
AN - SCOPUS:0020263963
SN - 0009-9236
VL - 32
SP - 628
EP - 634
JO - Clinical Pharmacology and Therapeutics
JF - Clinical Pharmacology and Therapeutics
IS - 5
ER -