What the FDA labels say about taking them together
Diclofenac and lithium
Diclofenac's FDA label of February 11, 2025 names lithium in its drug interactions (prescription label) section; lithium's label does not name diclofenac itself but warns about its class (NSAIDs (nonsteroidal anti-inflammatory drugs)). The diclofenac label: “NSAIDs have produced elevations in plasma lithium levels and reductions in renal lithium clearance. The mean minimum lithium concentration increased 15%, and the renal clearance decreased by approximately 20%. …”
Check it at the source: the diclofenac FDA label on DailyMed (effective February 11, 2025, Haleon US Holdings LLC); the lithium FDA label on DailyMed (effective December 23, 2025, Glenmark Pharmaceuticals Inc., USA).
What does the diclofenac label say about lithium?
Diclofenac label, drug interactions (prescription label)Lithium NSAIDs have produced an elevation of plasma lithium levels and a reduction in renal lithium clearance.
Licart label (IBSA Pharma Inc., April 2, 2026), drug interactionsClinical Impact: NSAIDs have produced elevations in plasma lithium levels and reductions in renal lithium clearance. The mean minimum lithium concentration increased 15%, and the renal clearance decreased by approximately 20%. This effect has been attributed to NSAID inhibition of renal prostaglandin synthesis. Intervention: During concomitant use of LICART and lithium, monitor patients for signs of lithium toxicity.
Source: FDA drug label (Licart, NDA206976), IBSA Pharma Inc., effective April 2, 2026 (SPL set 851c8b39-6056-4bbc-812e-b9b13977c1ac), via openFDA
Source: FDA drug label (Voltaren Arthritis Pain), Haleon US Holdings LLC, effective February 11, 2025 (SPL set 30a94282-0892-442a-aa10-6525cbd4fe88), via openFDA; the full label on DailyMed
What does the lithium label say about diclofenac?
Lithium's label does not name diclofenac itself; it warns about its class (NSAIDs (nonsteroidal anti-inflammatory drugs)):
Lithium label, drug interactionsDiuretics, NSAID, renin-angiotensin system antagonists, or metronidazole may increase lithium serum concentrations.
Lithium label, drug interactionsReduce lithium dosage based on serum lithium concentration and clinical response [see Dosage and Administration ( 2.3 ), Warning and Precautions ( 5.3 )]. Non-Steroidal Anti-inflammatory Drugs (NSAID)
Source: FDA drug label (Lithium Carbonate), Glenmark Pharmaceuticals Inc., USA, effective December 23, 2025 (SPL set 63b3790f-a9b5-47f4-bae1-ddf8b43c13c1), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Diclofenac | Lithium | |
|---|---|---|
| Labeled for | Pain, Osteoarthritis, Rheumatoid arthritis, Migraine | Bipolar disorder |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.0619 per tablet 75 mg tablet | $0.104 per capsule 300 mg capsule |
| Shortage now | A presentation being discontinued | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once