Are lithium capsules and tablets (lithium carbonate) interchangeable?

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Last updated: June 20, 2025View editorial policy

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From the FDA Drug Label

Lithium Carbonate Capsules USP 150 mg: Size ‘4’ two piece opaque white hard gelatin capsules imprinted with ‘150’ on body & ‘G220’ on cap. They are supplied by State of Florida DOH Central Pharmacy as follows: NDCStrengthQuantity/FormColorSource NDC 53808-0704-1300 mg30 TABLETOpaque68462-221-10

The FDA drug label does not answer the question.

From the Research

Lithium carbonate capsules and tablets are generally interchangeable when taken at the same dose, but patients should not switch forms without consulting their healthcare provider. Both formulations contain the same active ingredient (lithium carbonate) and deliver the same therapeutic effect when properly dosed. However, there may be slight differences in how quickly the medication is absorbed based on the specific formulation and manufacturer. When switching between forms, blood lithium levels should be monitored to ensure they remain within the therapeutic range (typically 0.6-1.2 mEq/L) 1.

Key Considerations

  • Patients should always take lithium with food and maintain consistent salt and fluid intake to prevent fluctuations in lithium levels.
  • It's also important to continue taking the medication exactly as prescribed, at the same times each day, even when switching forms.
  • Lithium has a narrow therapeutic window, meaning the difference between an effective dose and a toxic dose is small, which is why any changes to the medication regimen should be supervised by a healthcare provider.
  • The renal function of patients on long-term lithium treatment should be closely monitored, as prolonged lithium treatment may be a risk factor for progressive renal impairment 1.
  • Other medications, such as diuretics and nonsteroidal anti-inflammatory drugs (NSAIDs), may interact with lithium and affect its levels, so patients should inform their healthcare provider about all medications they are taking 2.

Monitoring and Supervision

  • Regular monitoring of blood lithium levels and renal function is essential to ensure safe and effective treatment.
  • Patients should be aware of the signs of lithium toxicity, such as tremors, confusion, and seizures, and seek medical attention immediately if they experience any of these symptoms.
  • Healthcare providers should be cautious when prescribing lithium to patients with pre-existing renal disease or those taking other medications that may interact with lithium.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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