Lithium

Question 1

what is lithium?

Answer 1

mood stabilising drug

Question 2

what is the therapeutic range of lithium?

Answer 2

0.4-1.0 mmol/L

Question 3

what organ excrets lithium?

Answer 3

kidney

Question 4

what are the adverse effects of lithium?

Answer 4

• nausea/vomiting, diarrhoea
• fine tremor
• nephrotoxicity
• thyroid enlargement
• weight gain
• idiopathic intracranial hypertension
• leucocytosis
• hyperparathryoidism –> hypercalcaemia

Question 5

what ECG changes can be seen with a patient on lithium?

Answer 5

T wave flattening/inversion

Question 6

when should a sample for lithium levels be taken?

Answer 6

12 hours post-dose

Question 7

when are lithium levels checked?

Answer 7

• beginning = weekly
• after each dose change
• stable = 3 months

Question 8

when are thyroid and renal functions checked in a patient on lithium?

Answer 8

every 6 months

Question 9

what concentration leads to lithium toxicity?

Answer 9

> 1.5 mmol/L

Question 10

what can precipitate lithium toxicity?

Answer 10

• dehydration
• renal failure
• drugs

Question 11

what drugs can precipitate lithium toxicity?

Answer 11

• thiazides
• ACEi/angiotensin II receptor blockers
• NSAIDs
• metronidazole

Question 12

what are the features of lithium toxicity?

Answer 12

• coarse tremor
• hyperreflexia
• acute confusion
• polyuria
• seizure
• coma

Question 13

is fine tremor a sign of lithium toxicity?

Answer 13

no it is seen in therapeutic levels

Question 14

how is lithium toxicity managed?

Answer 14

• volume resuscitation with normal saline
• severe = haemodialysis
• sodium bicarbonate