Lithium side effects in relation to dose and to levels and gradients of lithium in plasma.

The relation between lithium dose, lithium concentrations, and lithium gradients in plasma and the side effects tremor, nausea, abdominal pains, and loose bowels was studied in 19 subjects. Rapidly dissolving lithium carbonate tablets were used. Tremor was related to higher doses, to higher concentrations, and to higher gradients of lithium in plasma. Nausea was related to higher gradients. Abdominal pain and loose bowels showed no relation to doses, levels or gradients. Concentrations of lithium were dose-dependent, while gradients were relatively independent of dose.