Drug interactions
Diflunisal + Lithium
Severity: Major
Diflunisal and Lithium: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Diflunisal can raise serum lithium concentrations, risking lithium toxicity with tremor, confusion, ataxia and gastrointestinal symptoms. The effect can develop within days of starting the NSAID.
What this interaction means in plain words
Diflunisal and Lithium can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Diflunisal belongs to Musculoskeletal; Lithium belongs to Central Nervous System.
Why it happens
NSAID inhibition of renal prostaglandins reduces renal lithium clearance.
What to do
Avoid if possible; otherwise check lithium levels within a week of starting or changing diflunisal and reduce lithium dose as needed. Counsel on signs of toxicity.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Diflunisal
- Diflunisal + Ketorolac Contraindicated
- Diflunisal + Ketorolac intranasal Contraindicated
- Acemetacin + Diflunisal Major
- Acetazolamide + Diflunisal Major
- Alteplase + Diflunisal Major
- Amiloride + Diflunisal Major
Other interactions of Lithium
- Lithium + Thioridazine Contraindicated
- Lithium + Vandetanib Contraindicated
- Aceclofenac + Lithium Major
- Acemetacin + Lithium Major
- Amisulpride + Lithium Major
- Amlodipine-benazepril + Lithium Major
Frequently asked questions
Can I take Diflunisal with Lithium?
MediHelp rates the interaction as major. Diflunisal and Lithium can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Diflunisal can raise serum lithium concentrations, risking lithium toxicity with tremor, confusion, ataxia and gastrointestinal symptoms. The effect can develop within days of starting the NSAID.
How serious is the interaction between Diflunisal and Lithium?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible; otherwise check lithium levels within a week of starting or changing diflunisal and reduce lithium dose as needed. Counsel on signs of toxicity.
What other medicines interact with Diflunisal?
MediHelp also lists interactions of Diflunisal with, for example, Ketorolac, Ketorolac intranasal, Acemetacin. The full list is on the Diflunisal page.
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