Lithium Carbonate

LITHIUM CARBONATE- lithium carbonate tablet
REMEDYREPACK INC.

WARNING: LITHIUM TOXICITY

Lithium toxicity is closely related to serum lithium concentrations, and can occur at doses close to therapeutic concentrations. Facilities for prompt and accurate serum lithium determinations should be available before initiating treatment [see Dosage and Administration (2.3), Warnings and Precautions (5.1)] .

1 INDICATIONS AND USAGE

Lithium is a mood-stabilizing agent indicated as monotherapy for the treatment of bipolar I disorder:

  • Treatment of acute manic and mixed episodes in patients 7 years and older [see Clinical Studies (14)]
  • Maintenance treatment in patients 7 years and older [see Clinical Studies (14)]

2 DOSAGE AND ADMINISTRATION

2.1 Pre-treatment Screening

Before initiating treatment with lithium, renal function, vital signs, serum electrolytes, and thyroid function should be evaluated. Concurrent medications should be assessed, and if the patient is a woman of childbearing potential, pregnancy status and potential should be considered.

2.2 Recommended Dosage

See Table 1 for dosage recommendations for acute and maintenance treatment of bipolar I disorder in adult and pediatric patients (7 to 17 years). Obtain serum lithium concentration assay after 3 days, drawn 12 hours after the last oral dose and regularly until patient is stabilized. Fine hand tremor, polyuria, and thirst may occur during initial therapy for the acute manic phase and may persist throughout treatment. Nausea and general discomfort may also appear during the first few days of lithium administration. These adverse reactions may subside with continued treatment, concomitant administration with food, or temporary reduction or cessation of dosage.

Table 1. Lithium Dosing for Bipolar I Disorder

Patient Group Formulation Starting Dose Dose Titration Acute Goal Maintenance Goal
Serum Level Usual Dose Serum Level Usual Dose
Adult and Pediatric Patients over 30 kg Tablets 300 mg three times daily 300 mg every 3 days 0.8 to 1.2 mEq/L 600 mg two to three times daily 0.8 to 1.0 mEq/L 300 to 600 mg two to three times daily
Pediatric Patients 20 to 30 kg Tablets 300 mg twice daily 300 mg weekly 600 to 1500 mg in divided doses daily 600 to 1200 mg in divided doses daily

Each 5 mL of Lithium Oral Solution contains 8 mEq of lithium ion (Li +) which is equivalent to the amount of lithium in 300 mg of lithium carbonate. See Table 2 for lithium carbonate and lithium oral solution dose conversion.

Table 2. Lithium Carbonate and Lithium Oral Solution Dose Conversion

Lithium Carbonate Tablets Lithium Oral Solution
150 mg 4 mEq (2.5 mL)
300 mg 8 mEq (5 mL)
600 mg 16 mEq (10 mL)

2.3 Serum Lithium Monitoring

Blood samples for serum lithium determination should be drawn immediately prior to the next dose when lithium concentrations are relatively stable (i.e., 12 hours after the previous dose). Total reliance must not be placed on serum concentrations alone. Accurate patient evaluation requires both clinical and laboratory analysis.
In addition to regular monitoring of serum lithium concentrations for patients on maintenance treatment, serum lithium concentrations should be monitored after any change in dosage, concurrent medication (e.g., diuretics, non-steroidal anti- inflammatory drugs, renin-angiotensin system antagonists, or metronidazole), marked increase or decrease in routinely performed strenuous physical activity (such as an exercise program) and in the event of a concomitant disease [See Boxed Warning, Warnings and Precautions (5.1), Drug Interactions (7.1)]. Patients abnormally sensitive to lithium may exhibit toxic signs at serum concentrations that are within what is considered the therapeutic range. Geriatric patients often respond to reduced dosage, and may exhibit signs of toxicity at serum concentrations ordinarily tolerated by other patients [see Specific Populations (8.5)].

2.4 Dosage Adjustments during Pregnancy and the Postpartum Period

If the decision is made to continue lithium treatment during pregnancy, monitor serum lithium concentrations and adjust the dosage as needed in a pregnant woman because renal lithium clearance increases during pregnancy. Avoid sodium restriction or diuretic administration. To decrease the risk of postpartum lithium intoxication, decrease or discontinue lithium therapy two to three days before the expected delivery date to reduce neonatal concentrations and reduce the risk of maternal lithium intoxication due to the change in vascular volume which occurs during delivery. At delivery, vascular volume rapidly decreases and the renal clearance of lithium may decrease to pre-pregnancy concentrations. Restart treatment at the preconception dose when the patient is medically stable after delivery with careful monitoring of serum lithium concentrations [see Warnings and Precautions (5.1) and Use in Specific Populations (8.1)].

2.5 Dosage Adjustments for Patients with Renal Impairment

Start patients with mild to moderately impaired renal function (creatinine clearance 30 to 89 mL/min evaluated by Cockcroft-Gault) with dosages less than those for patients with normal renal function [see Dosage and Administration (2.2)]. Titrate slowly while frequently monitoring serum lithium concentrations and monitoring for signs of lithium toxicity. Lithium is not recommended for use in patients with severe renal impairment (creatinine clearance less than 30 mL/min evaluated by Cockcroft-Gault) [see Use in Specific Populations (8.6)].

3 DOSAGE FORMS AND STRENGTHS

Each 300 mg tablet for oral administration contains: lithium carbonate USP and is white to off-white, circular, biconvex, uncoated tablet debossed with “430” on one side and break line on other side.

4 CONTRAINDICATIONS

Lithium is contraindicated in patients with known hypersensitivity to any inactive ingredient in the lithium carbonate tablet [see Adverse Reactions (6)].

5 WARNINGS AND PRECAUTIONS

5.1 Lithium Toxicity

The toxic concentrations for lithium (≥1.5 mEq/L) are close to the therapeutic range (0.8 to 1.2mEq/L). Some patients abnormally sensitive to lithium may exhibit toxic signs at serum concentrations that are considered within the therapeutic range [see Boxed Warning, Dosage and Administration (2.3)]. Lithium may take up to 24 hours to distribute into brain tissue, so occurrence of acute toxicity symptoms may be delayed.

Neurological signs of lithium toxicity range from mild neurological adverse reactions such as fine tremor, lightheadedness, lack of coordination, and weakness; to moderate manifestations like giddiness, apathy, drowsiness, hyperreflexia, muscle twitching, ataxia, blurred vision, tinnitus, and slurred speech; and severe manifestations such as clonus, confusion, seizure, coma, and death. In rare cases, neurological sequelae may persist despite discontinuing lithium treatment and may be associated with cerebellar atrophy. Cardiac manifestations involve electrocardiographic changes, such as prolonged QT interval, ST and T-wave changes and myocarditis. Renal manifestations include urine concentrating defect, nephrogenic diabetes insipidus, and renal failure. Respiratory manifestations include dyspnea, aspiration pneumonia, and respiratory failure. Gastrointestinal manifestations include nausea, vomiting, diarrhea, and bloating. No specific antidote for lithium poisoning is known [see Overdosage (10)].

The risk of lithium toxicity is increased by:

  • Recent onset of concurrent febrile illness
  • Concomitant administration of drugs which increase lithium serum concentrations by pharmacokinetic interactions or drugs affecting kidney function [see Drug Interactions (7)].
  • Acute ingestion
  • Impaired renal function
  • Volume depletion or dehydration
  • Significant cardiovascular disease
  • Changes in electrolyte concentrations (especially sodium and potassium)

Monitor for signs and symptoms of lithium toxicity. If symptoms occur, decrease dosage or discontinue lithium treatment.

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