Lithium

Chemical

An alkali metal →chemical element 3

Use

Tx & prevent manic states of Bipolar Disorder

Presentation

Tablets

Dose

0.4 – 1.2g/day

Route

PO

Onset

6 – 10 days

MoA (mechanism)

Unknown

  • Stabilises membranes
  • Alter central NT function

→Chemically resembles Na+ & K+ which are in the same group of the Periodic Table

PD

CNS

  • ↓seizure threshold
  • ↑muscle tone

CVS – TW ↓on ECG

GU – antagonism of ADH →polyuria & polydipsia

Metabolic

  • Na+ retention (2° ↑ aldosterone)
  • ↑Ca2+
  • ↑Mg2+
  • Insulin like effects on CHO metabolism

PK

A

100% OBA

D

No PPB

VD 0.5 – 1.1L/kg

M

No metabolism

E

95% in urine

t ½ B 30hrs

Removed by HD

Adverse Effects

Therapeutic levels

  • Thyroid function disturbances
  • Weight gain
  • Tremor
  • Pretibial oedema

Lithium toxicity

  • N&V
  • Abdominal pain
  • Diarrhoea
  • Ataxia
  • Convulsions
  • Coma
  • Arrhythmias
  • Death