Lithium Carbonate and Psyllium: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Psyllium
Lithium Carbonate
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Decreased plasma levels and effectiveness of lithium
Interaction Deep Dive
A case report demonstrates decreased lithium levels despite dosage escalations when given concomitantly with psyllium. Further study is needed before a definitive drug-herb interaction is confirmed but this case report suggests impairment in lithium absorption secondary to psyllium administration1.
Why it happens (mechanism)
Impaired lithium absorption
Literature reports
1 report — tap to read
a) A 47-year-old woman prescribed lithium citrate at a dose comparable to 300 mg lithium carbonate three times daily (lithium blood level: 0.53 millimoles/liter (mmol/L)) initiated treatment with ispaghula husk (psyllium), one teaspoon in water twice daily. Lithium citrate was increased to 10 mL twice daily but her lithium level decreased to 0.40 mmol/L five days later. Within four days of discontinuation of ispaghula husk at the same lithium dose, the lithium level increased to 0.76 mmol/L. The authors concluded that while a specific mechanism could be not identified, they presumed the hydrophilic properties of ispaghula husk sequestered lithium and impaired its absorption 1.
Common questions
Can I take Lithium Carbonate and Psyllium together?
Decreased plasma levels and effectiveness of lithium Always confirm with your pharmacist or prescriber before making any change.
How serious is the Lithium Carbonate and Psyllium interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Lithium Carbonate or Psyllium need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (1)
- Perlman BB: Interaction between lithium salts and ispaghula husk. Lancet 1990; 1:416. PubMed
Keep reading about Lithium Carbonate
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