Lithium



Background

  • Primarily used for uni / bipolar depression
  • Narrow therapeutic range (0.4 - 1.0 mmol/). Toxicity at 2.0 mmol/l
  • Acute toxicity
    • Thirst, polyuria, tremor, dysarthria, ataxia, arrhythmia & coma
  • Chronic toxicity
    • Acne, hypothyroidism, alopecia & psoriasis

Toxicity

  • Readily absorbed in GI tract over 4 - 6 hours post overdose.
  • Widely distributed
  • Not protein bound - circulates as simple cation
  • Renal excretion
  • Elimination t1/2 usually 24 hours but dependant upon renal function
  • Acute toxicity usually occurs on background of chronic with altered metabolism eg dehydration

Management

Admit all with symptoms of toxicity or levels > 2mmol/l

Supportive management - A, B, C with correction fluid / electrolyte imbalance

Avoid charcoal

GI Tract decontamination unhelpful

Whole bowel irrigation MAY be useful (no evidence either way) if sustained release preparation ingested

Avoid forced diuresis

Haemodialysis (repeated to treat rebound post treatment levels) very effective

Haemodialysis indications (severe / life threatening overdose)



Content by - Dr Íomhar O' Sullivan. 12/01/2001. Reviewed by Dr ÍOS 08/02/2003, 10/04/2004, 18/05/2005, 13/05/2007. next review 13/05/2008