Lithium

Lithium

Lithium is mood stabilising drug used most commonly prophylactically in bipolar disorder but also as an adjunct in refractory depression. It has a very narrow therapeutic range (0.4-1.0 mmol/L) and a long plasma half-life being excreted primarily by the kidneys.

Mechanism of action - not fully understood, two main theories:

• interferes with inositol triphosphate formation
• interferes with cAMP formation

Adverse effects

• nausea/vomiting, diarrhoea
• fine tremor
  Lithium may cause tremor
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  Importance: 21
• nephrotoxicity
  Lithium may cause nephrotoxicity
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  Importance: 14
  : polyuria, secondary to nephrogenic diabetes insipidus
  Lithium may cause diabetes insipidus
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  Importance: 3
• thyroid enlargement, may lead to hypothyroidism
  Hypothyroidism is the most common endocrine disorder developing as a result of chronic lithium toxicity
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  Importance: 23
• ECG: T wave flattening/inversion
• weight gain
  Lithium may cause weight gain
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  Importance: 9
• idiopathic intracranial hypertension
  Lithium may cause intracranial hypertension
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  Importance: 32
• leucocytosis
  leucocytosis
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• hyperparathyroidism and resultant hypercalcaemia
  Long-term lithium use can result in hyperparathyroidism and resultant hypercalcaemia
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  Importance: 13

Monitoring of patients on lithium therapy

• inadequate monitoring of patients taking lithium is common - NICE and the National Patient Safety Agency (NPSA) have issued guidance to try and address this. As a result it is often an exam hot topic
• when checking lithium levels, the sample should be taken 12 hours post-dose
  12 hours post-dose
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• 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
  Lithium levels should be checked every 3 months once a stable dose has been achieved
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  Importance: 97
• after a change in dose, lithium levels should be taken a week later and weekly until the levels are stable.
  after a change in dose, lithium levels should be taken a week later and weekly until the levels are stable.
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• thyroid and renal function should be checked every 6 months
  thyroid and renal function should be checked every 6 months
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• patients should be issued with an information booklet, alert card and record book

+PassMedicine Notes

Lithium is mood stabilising drug used most commonly prophylactically in bipolar disorder but also as an adjunct in refractory depression. It has a very narrow therapeutic range (0.4-1.0 mmol/L) and a long plasma half-life being excreted primarily by the kidneys.

Mechanism of action - not fully understood, two main theories:

• interferes with inositol triphosphate formation
• interferes with cAMP formation

Adverse effects

• nausea/vomiting, diarrhoea
• fine tremor
• nephrotoxicity: polyuria, secondary to nephrogenic diabetes insipidus
• thyroid enlargement, may lead to hypothyroidism
• ECG: T wave flattening/inversion
• weight gain
• idiopathic intracranial hypertension
• leucocytosis
• hyperparathyroidism and resultant hypercalcaemia

Monitoring of patients on lithium therapy

• inadequate monitoring of patients taking lithium is common - NICE and the National Patient Safety Agency (NPSA) have issued guidance to try and address this. As a result it is often an exam hot topic
• when checking lithium levels, the sample should be taken 12 hours post-dose
• 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.
• thyroid and renal function should be checked every 6 months
• patients should be issued with an information booklet, alert card and record book