Lithium Overdose

First Things First

• Metal similar to potassium, magnesium and sodium
• Currently used in treatment of bipolar disorder for the mania and as a mood stabilizer
• Narrow toxic-to-therapeutic range ratio
• Tablets and capsules
  • 300-mg tablets have 8 mEq of lithium
  • Also comes in 150-mg and 600-mg capsules
  • Extended release, 300 mg, 450 mg
  • Syrup has 8 mEq/5 mL.
  • Normal serum level is 0.7-1.2 mEq/L.
• Mechanism of action is not well understood.
  • May stabilize cell membranes
  • Inhibits NE to interfere with cAMP
  • Enhances effects of serotonin
  • Rapidly absorbed into serum from GI tract and therefore peaks rapidly
  • Syrup: 40 min
  • Rapid release: 2-4 hr
  • Extended release: 4-12 hrs
• Renal elimination 95%
  • Sweat/saliva/milk: 5%
  • Prolonged & delayed absorption
  • Decreased elimination
  • Intracellular lithium build-up
• It is not metabolized.
  • No protein binding
  • We reabsorb more when we are in a low-sodium or low-volume state.
• Lithium modulates signals affecting the cytoskeleton, thereby stabilizing moods.