The mechanism of action of lithium is not known. It is rapidly absorbed, has a small volume of distribution, and is excreted in the urine unchanged (there is no metabolism of lithium). The half-life of Lithium is 18 to 30 hours. Absorption is lower on an empty stomach .
Lithium can cause several adverse effects. Normally the side effects are dose-related . Notable side effects include:
Lithium modifies sodium transport in nerve and muscle cells. It alters the metabolism of neurotransmitters, specifically catecholamines, and serotonin. It may alter intracellular signaling via second messenger systems by inhibition of inositol monophosphate. This inhibition, in turn, affects neurotransmission through the phosphatidylinositol secondary messenger system .
A study suggests that lithium exposure through drinking water during pregnancy may impair the calcium homeostasis, particularly vitamin D. The results substatiates the need for control of lithium in drinking water, including bottled water .
Lithium decreases protein kinase C activity which alters genomic expression associated with neurotransmission .
Lithium is thought to increase cytoprotective proteins and possibly activates neurogenesis and increases gray matter volume .