Lithium concentrations in saliva, plasma and red blood cells of patients given lithium acetate

Publisher Website
Google Scholar
Abstract
Lithium concentrations in saliva, plasma and red blood cells were measured in: 1) six hospitalized patients under long-term lithium therapy, at 2, 5, 9 and 24 hours after oral doses of 24 mEq Liacetate and 2 or 12 hours after 8 mEq Li acetate; and 2) 10 outpatients under chronic lithium treatment at two occasions 8 days apart. With changing plasma concentrations, [Li] saliva varied without any notable time lag. [Li] saliva was always much higher than [Li] plasma. The ratio [Li] saliva/ [Li] plasma water averaged 3.2 ± 0.2 in 62 determinations, but varied widely at different times after oral lithium in the same individuals and less widely between different individuals. “Prediction” of plasma lithium concentration from measured [Li] saliva appears hazardous, and may provide reliable indications only if [Li] saliva is measured repeatedly. Salivary lithium concentrations were not correlated with either potassium or sodium concentrations. Lithium concentrations in red blood cells were always lower than in plasma: [Li] red blood cell water/ [Li] plasma water averaged 0.37 ± 0.03. With changing plasma concentrations, rise and fall of red blood cell lithium lagged considerably behind plasma changes. This resulted in a rise of the red blood cell/plasma concentration ratio from a very low value 2 hours after an oral dose to a rather high value 24 hours after an oral dose.