lithium

Absorption: Completely absorbed after oral administration.

Distribution: Widely distributed into many tissues and fluids; CSF levels are 50% of plasma levels.

Metabolism/Excretion: Excreted almost entirely unchanged by the kidneys.

Half-Life: 20–27 hr.

Time/Action Profile ⬆ ⬇

(antimanic effects)

ROUTE	ONSET	PEAK	DURATION
PO, PO-ER	5–7 days	10–21 days	days

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Brugada syndrome;
Some products contain alcohol or tartrazine and should be avoided in patients with known hypersensitivity or intolerance;
OB: Pregnancy;
Lactation: Lactation.

Use Cautiously in:

Significant cardiovascular disease, renal impairment, dehydration, fever, or hyponatremia (↑ risk of lithium toxicity);
Diabetes mellitus;
Pedi: Children <7 yr (safety and effectiveness not established);
Geri: Initial dosage ↓ recommended in older adults.

Adv. Reactions/Side Effects ⬆ ⬇

CV: ECG changes, arrhythmias, edema, hypotension, unmasking of Brugada syndrome

Derm: acneiform eruption, folliculitis, alopecia, diminished sensation, DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS), pruritus

EENT: blurred vision, tinnitus

Endo: hypothyroidism, goiter, hyperglycemia, hyperparathyroidism, hyperthyroidism

F and E: hypercalcemia, hyponatremia

GI: abdominal pain, anorexia, bloating, diarrhea, nausea, dry mouth

GU: polyuria, glycosuria, nephrogenic diabetes insipidus, renal impairment.

Hemat: leukocytosis

Metab: weight gain

MS: muscle weakness, rigidity

Neuro: fatigue, headache, memory impairment, tremor, aphasia, ataxia, confusion, dizziness, drowsiness, dysarthria, dysgeusia, hyperirritability, PSEUDOTUMOR CEREBRI, psychomotor retardation, restlessness, sedation, SEIZURES, stupor

Misc: SEROTONIN SYNDROME

Interactions ⬆ ⬇

Drug-drug:

May prolong the action of neuromuscular blocking agents.
↑risk of neurologic toxicity with calcium channel blockers, phenytoin, or carbamazepine.
Diuretics, NSAIDs, ACE inhibitors, angiotensin II receptor blockers, and metronidazole may ↑ levels and risk of toxicity.
Hypothyroid effects may be additive with potassium iodide or antithyroid agents.
Aminophylline, acetazolamide, theophylline, and sodium bicarbonate may ↑ renal elimination and ↓ effectiveness.
Psyllium may ↓ levels.
Drugs that affect serotonergic neurotransmitter systems, including tricyclic antidepressants, SSRIs, SNRIs, fentanyl, buspirone, tramadol, amphetamines, and triptans, may ↑ risk of serotonin syndrome.
Antipsychotics may ↑ risk of developing an encephalopathic syndrome (e.g., weakness, lethargy, fever, tremulousness and confusion, extrapyramidal symptoms, leukocytosis, ↑ BUN, ↑ fasting blood glucose); monitor closely.
SGLT2 inhibitors may ↓ levels and effectiveness.

Drug-Natural Products:

Caffeine-containing herbs (cola nut, guarana, mate, tea, coffee) may ↓ levels and effectiveness.
↑risk of serotonergic side effects, including serotonin syndrome, with St. John’s wort.

Drug-Food:

Large changes in sodium intake may ↑ renal excretion and ↓ levels and effectiveness of lithium.

Route/Dosage ⬆ ⬇

Precise dosing is based on serum lithium levels. 300 mg lithium carbonate contains 8–12 mEq lithium.
PO (Adults and Children ≥7 yr and >30 kg): Tablets/capsules/liquid: 300 mg 3 times daily initially; ↑ by 300 mg/day every 3 days; usual dose for treatment of acute manic and mixed episodes = 600 mg 2–3 times daily; usual maintenance dose = 300–600 mg 2–3 times daily.
PO (Adults and Children >12 yr): Extended-release tablets: 450–900 mg twice daily or 300–600 mg 3 times daily initially; usual maintenance dose is 450 mg twice daily or 300 mg 3 times daily.
PO (Children ≥7 yr and 20–30 kg): Tablets/capsules/liquid: 300 mg twice daily initially; ↑ by 300 mg/wk; usual dose for treatment of acute manic and mixed episodes = 600–1500 mg/day in divided doses; usual maintenance dose = 600–1200 mg/day in divided doses.

Availability ⬆ ⬇

(Generic available)

Immediate-release tablets: 300 mg
Immediate-release capsules: 150 mg; 300 mg; 600 mg
Extended-release tablets: 300 mg; 450 mg
Oral solution: 300 mg (8 mEq lithium)/5 mL

Assessment ⬆ ⬇

Assess and monitor mental status (orientation, mood, behavior, affect). Assess for suicidal tendencies and initiate suicide precautions if indicated. Inform health care provider if patient demonstrates significant changes in mood or behavior.
Monitor intake and output. Report significant changes in totals. Unless contraindicated, fluid intake of ≥2000–3000 mL/day should be maintained. Weight should also be monitored at least every 3 mo.
Assess for signs and symptoms of serotonin syndrome (confusion, delirium, agitation, coma, dilated pupils, tachycardia, hyperthermia, shivering, hyperreflexia, muscle rigidity, hypertension, vomiting, diarrhea, seizures). ↑ risk of serotonin syndrome with concurrent use of other serotonergic drugs (SSRIs, SNRIs, triptans); monitoring recommended; discontinuation may be required.

Lab Test Considerations:

Evaluate renal and thyroid function, WBC with differential, electrolytes, and glucose periodically during therapy.

Toxicity and Overdose:

Lithium toxicity is closely related to serum lithium concentrations and can occur at doses close to therapeutic concentrations. Monitor serum lithium concentrations twice weekly during initiation of therapy and every 2 mo during chronic therapy. Draw blood samples in the morning, immediately before next dose. Therapeutic levels range from 0.5–1.5 mEq/L for acute mania and 0.6–1.2 mEq/L for long-term control. Serum concentrations should not exceed 2.0 mEq/L.
- Assess patient for signs and symptoms of lithium toxicity (vomiting, diarrhea, slurred speech, light-headedness, ↓ coordination, drowsiness, muscle weakness, tremor, twitching). If these occur, report before administering next dose.

Implementation ⬆ ⬇

Do not confuse lithium carbonate with lanthanum carbonate.
PO: Administer with food or milk to ↓ GI irritation. DNC: Extended-release preparations should be swallowed whole; do not break, crush, or chew.

Patient/Family Teaching ⬆ ⬇

Explain the purpose and side effects of lithium. Instruct patient to take medication as directed, even if feeling well. Take missed doses as soon as remembered unless within 2 hr of next dose (6 hr if extended release). Advise patient to read Patient Information before starting and with each Rx refill in case of changes.
Emphasize the importance of periodic lab tests to monitor for lithium toxicity.
Lithium may cause dizziness or drowsiness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
Low sodium levels may predispose patient to toxicity. Advise patient to drink 2000–3000 mL fluid each day and follow a diet with consistent and moderate sodium intake. Excessive amounts of coffee, tea, and cola should be avoided because of diuretic effect. Avoid activities that cause excess sodium loss (heavy exertion, exercise in hot weather, saunas). Notify health care provider of fever, vomiting, and diarrhea, which also cause sodium loss.
Advise patient that weight gain may occur. Review principles of a low-calorie diet.
Advise patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care provider before taking other medications, especially NSAIDs and St. John's wort.
Review side effects and symptoms of toxicity with patient. Instruct patient to stop medication and report signs of toxicity to health care provider promptly.
Advise patient to notify health care provider if fainting, light-headedness, palpitations, or difficulty breathing occur, as these may be symptoms of Brugada syndrome.
Rep: May cause fetal harm. Advise women of reproductive potential to use contraception during therapy, consult health care provider if pregnancy is planned or suspected, and avoid breastfeeding. Monitor breastfed infants for signs and symptoms of lithium toxicity (hypertonia, hypothermia, cyanosis, ECG changes).

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇