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