Phenytoin disposition in smokers and nonsmokers.
Smoking habit did not affect the disposition kinetics of intravenously administered phenytoin. Phenyoin was given to 8 smokers and 8 nonsmokers and plasma concentrations of phenytoin were determined over a three day period by GLC and RIA techniques. Nonlinear least squares computer fit of the plasma concentration-time data yielded coefficients of a biexponential equation for calculation of half-lives (t1/2beta), clearances (ClB) and volumes of distribution. There were no statistically significant differences in these parameters with respect to either sex or smoking habit. However, more variable t1/2beta's were noted in the smoking group. No differences in serum protein binding between smoking and nonsmoking groups were found. Serum thiocyanate concentrations were used as a measure of smoking habit. There was no significant correlation between thiocyanate concentrations and t1/2beta or ClB. Attemps to correlate phenytoin ClB with basal metabolic rate also failed.
D000328:Adult; D000368:Aged; D001798:Blood Proteins / Q000378:metabolism; D005260:Female; D006207:Half-Life; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D010672:Phenytoin / Q000097:blood / Q000378:metabolism*; D011485:Protein Binding; D012907:Smoking / Q000378:metabolism*; D013861:Thiocyanates / Q000097:blood; D013997:Time Factors
D001798:Blood Proteins; D013861:Thiocyanates; D010672:Phenytoin