Single dose pharmacokinetics of lithium and prediction of maintenance dose in manic depressive patients.
Pharmacokinetics of lithium was studied in 60 manic-depressive patients after an initial dose of 900 mg, in serial blood samples for 24 h. The values (mean +/- SD) obtained were peak serum Li concentration 0.81 +/- 0.18 mEq/l; time to peak 2.57 +/- 0.87 h; total Li clearance 33.2 +/- 15.5 ml/min; volume of distribution 0.62 +/- 0.26 l/kg; elimination rate constant 0.0514 +/- 0.02 h; area under serum concentration-time curve 16.41 +/- 11.41 mEq/1 h; serum half life 15.34 +/- 6.06 h. Thereafter, the applicability of various dose prediction methods was evaluated vis-a-vis the actual doses needed to attain steady state serum lithium concentration of 0.6-1.2 mEq/l in 46 patients. The method based on body weight was not found suitable. A nomographic method predicted higher doses in 27 patients, while Zetin's mathematical model predicted dose was in the range of +/- 150 mg of the actual dose in 21 patients. A method for predicting maintenance dose based on 24 h serum lithium level and body weight is suggested.
Valecha
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Department of Pharmacology, Maulana Azad Medical College, New Delhi.
Tayal
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Tripathi
K D
KD
D000328:Adult; D001714:Bipolar Disorder / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008094:Lithium / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological
D008094:Lithium