Toxicology & Substance Use · Topic 9 of 17

Lithium Toxicity

Toxicology · mood stabilizers

Lithium Toxicity

Chronic toxicity causes neurologic signs at modest levels. Stop lithium, give saline, and hemodialyze for a level above 4.0 with kidney impairment or severe neurologic signs.

Key numbers

Therapeutic lithium level 0.6–1.2 mEq/L0.6–1.2 mEq/L

Hemodialysis: level > 4.0 with kidney impairmentLi > 4.0 + AKI → HD

Dialysis suggested: level > 5.0 or confusionLi > 5.0 mEq/L

01 · The numberTherapeutic lithium level 0.6–1.2 mEq/L

The therapeutic steady-state lithium level is 0.6–1.2 mEq/L; mild toxicity usually appears at 1.5–2.5 mEq/L in chronic users.

02 · Defined byHemodialysis: level > 4.0 with kidney impairment

EXTRIP recommends extracorporeal removal when lithium is > 4.0 mEq/L with impaired kidney function, or with decreased consciousness, seizures or life-threatening dysrhythmias at any level.

03 · Don't confuseChronic toxicity: neurologic signs at lower levels

Acute overdose in a lithium-naive patient brings prominent GI symptoms with high levels and few neurologic signs; chronic toxicity in a maintenance patient brings neurologic signs at levels as low as 1.5 mEq/L.

Causes & risk factors

Why it happens

Thiazides, ACE inhibitors and NSAIDs raise lithiumToxicity is more likely with older age, falling creatinine clearance and sodium loss (fever, vomiting, diarrhea, diuretics); thiazides, ACE inhibitors and NSAIDs other than aspirin raise lithium levels — avoid or monitor closely.

Presentation

What you'll see

Coarse tremor, hyperreflexia, confusion, then seizures must knowNeurotoxicity starts with coarse tremor, increased deep tendon reflexes, fasciculations, ataxia, headache, vomiting and confusion, and can progress to stupor, seizures and arrhythmias.

Diagnosis & monitoring

Work-up

Dialysis suggested: level > 5.0 or confusionEXTRIP also suggests extracorporeal removal for lithium > 5.0 mEq/L, significant confusion, or when the expected time to fall below 1.0 mEq/L with optimal care exceeds 36 hours.

Do right now

In this order

First moves

Stop lithium and give IV isotonic saline

→

No charcoal; whole-bowel irrigation for sustained-release

→

Hemodialysis: level > 4.0 with kidney impairmentLi > 4.0 + AKI → HD

Why each step

Stop lithium and give IV isotonic salineFirst steps: stop lithium and restore volume with IV isotonic saline; check kidney function, sodium and serial lithium levels.

No charcoal; whole-bowel irrigation for sustained-releaseActivated charcoal does not bind lithium; after a sustained-release ingestion, whole-bowel irrigation with polyethylene glycol may be used, though no decontamination has proven outcome benefit.

Hemodialysis: level > 4.0 with kidney impairmentEXTRIP recommends extracorporeal removal when lithium is > 4.0 mEq/L with impaired kidney function, or with decreased consciousness, seizures or life-threatening dysrhythmias at any level.

Management

Orders

Intermittent hemodialysis; recheck levels for reboundIntermittent hemodialysis is preferred (CRRT if unavailable); stop when lithium is < 1.0 mEq/L or the patient improves, or after 6 hours, then recheck levels over 12 hours for rebound.

Benzodiazepine for lithium seizuresTreat seizures with a benzodiazepine (diazepam) while arranging hemodialysis — seizures alone are an indication for extracorporeal removal.

Red flags & don'ts

Avoid harm

Nephrogenic diabetes insipidus from lithium complicationLithium causes nephrogenic diabetes insipidus (polyuria, dilute urine) and long-term hypothyroidism and hypercalcemia; see Diabetes Insipidus for treatment.

SILENT: lasting cerebellar damage after toxicity complicationThe syndrome of irreversible lithium-effectuated neurotoxicity (SILENT) leaves chronic, mainly cerebellar deficits even after lithium is stopped; it has no definitive treatment.

Acute or chronic lithium toxicity?

Commonly confused

Patient	Lithium-naive, single large ingestion
Leading symptoms	Gastrointestinal — nausea, vomiting, diarrhea
Level vs symptoms	High level, few or mild symptoms
Usual trigger	Intentional ingestion

More detail

Reference

Show 4 reference facts

Lithium is ideal for dialysis: a 7-Da cation, not protein-bound, with a volume of distribution of 0.5 L/kg rising to 0.7–0.9 L/kg over time.

Sodium polystyrene sulfonate has been proposed to enhance lithium elimination but has no clearly demonstrated role.

Acute-on-chronic poisoning is an overdose in a patient who already carries a body burden of lithium from maintenance therapy; serum levels and symptoms correlate poorly in all three patterns.

Routine lithium monitoring: level every 6 months and with every dose change, plus TSH and kidney function, because hypothyroidism and distal-tubule kidney damage develop over years.

Pearl

Acute overdose hits the gut first; chronic toxicity hits the brain at lower levels.

Sources · Decker BS et al. Extracorporeal treatment for lithium poisoning: systematic review and recommendations from the EXTRIP Workgroup. Clin J Am Soc Nephrol 2015;10:875–887 · Merck Manual Professional — Medications for Treatment of Bipolar Disorders (lithium) · Merck Manual Professional — Symptoms and Treatment of Specific Poisons (lithium salts) · Merck Manual Professional — General Principles of Poisoning · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).