LITHIUM

Question 1

Whats the therapeutic range of lithium?

Answer 1

very narrow therapeutic range (0.4-1.0 mmol/L)

Question 2

Where is lithium primarily excreted?

Answer 2

Kidneys

Question 3

Whats the moa of lithium?

Answer 3

Two theories:
interferes with inositol triphosphate formation
interferes with cAMP formation

Question 4

What are the adverse effects of lithium?

Answer 4

nausea/vomiting
diarrhoea
fine tremor
polyuria, secondary to nephrogenic diabetes insipidus
thyroid enlargement, may lead to hypothyroidism
weight gain
idiopathic intracranial hypertension
leucocytosis
hyperparathyroidism and resultant hypercalcaemia

Question 5

What ECG changes may you see when a pt takes lithium?

Answer 5

T wave flattening or inversion

Question 6

When checking lithium levels, when should the sample be taken post-dose?

Answer 6

12 hours postdose

Question 7

When should lithium monitoring be done?

Answer 7

after starting lithium levels should be performed weekly and after each dose change until concentrations are stable
once established, lithium blood level should ‘normally’ be checked every 3 months
after a change in dose, lithium levels should be taken a week later and weekly until the levels are stable.

Question 8

What monitoring other than lithium levels is required whilst taking lithium?

Answer 8

thyroid and renal function should be checked every 6 months