Lithium Mechanism of Action (MOA)

1.       1^st Line Tx Bipolar Disorder

Works like Na+. Blocks Na Channels

-Cell can’t become too positive

-Cell can’t become too negative

Mood Stabilizer (not acute Dz)

Blocks Relapse & acute Maniac Events

2.       Blocks ADH receptors V2

→ Nephro DI

SIADH Tx

3.       Fools kidney: Holds Li, let go Na

→Hyponatremia

Affects Electrolytes & ion transport

4.       Fools Thyroid (Resembles I)

→Hyponatremia

5.       Fools PTH receptors:

a.       ↑Ca+2, ↓PO4

6.       Phospho Inositol Cascade Inhibition

Inhibits dephospholiration of IP3->IP2, IP2-IP1 and IP1-IP

(inositol recycling steps → ↓PIP2)

7.       ↓DA & NE turnover (↓DA ↓ NE ↑Serotonin)

(IP3 is recycled back to PIP2 by the enzymes inositol monophosphate phosphatase (IMPase) and inositol polyphosphatase phosphatase (IPPase); both of which are inhibited by lithium)