Salivary and urinary lithium clearance while recumbent and upright.

Excretion of lithium in urine and saliva was studied in healthy males while recumbent and while upright, walking and standing quietly. An oral dose of 24.3 mEq of LI+ was taken as three lithium carbonate tablets 13 hr before clearance tests. Urinary lithium clearance decreased when posture was changed from recumbent to upright, but salivary lithium clearance was not affected by the abrupt change in posture. A correlation was observed while recumbent between lithium clearance in urine and saliva, but not while upright. The findings are related to the extrapolation of saliva lithium excretion data to urinary lithium clearance.