What the FDA labels say about taking them together
Lithium and triamterene
Triamterene's FDA label of December 5, 2024 names lithium in its drug interactions section; the lithium labels PlainMeds reads (4) do not name triamterene. The triamterene label: “Drug Interactions Caution should be used when lithium and diuretics are used concomitantly because diuretic-induced sodium loss may reduce the renal clearance of lithium and increase serum lithium levels with risk of …”
Check it at the source: the lithium FDA label on DailyMed (effective December 23, 2025, Glenmark Pharmaceuticals Inc., USA); the triamterene FDA label on DailyMed (effective December 5, 2024, Advanz Pharma (US) Corp.).
What does the lithium label say about triamterene?
Lithium's label (effective December 23, 2025) and its 3 other brand-application labels do not name triamterene in these sections. A label lists what its studies and reports found; it is not a complete list.
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
What does the triamterene label say about lithium?
Triamterene label, drug interactionsDrug Interactions Caution should be used when lithium and diuretics are used concomitantly because diuretic-induced sodium loss may reduce the renal clearance of lithium and increase serum lithium levels with risk of lithium toxicity.
Source: FDA drug label (Dyrenium), Advanz Pharma (US) Corp., effective December 5, 2024 (SPL set ebb177c0-d45d-4443-a85a-e76bd9931a42), 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
| Lithium | Triamterene | |
|---|---|---|
| Labeled for | Bipolar disorder | Heart failure, Edema (fluid retention) |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.104 per capsule 300 mg capsule | $5.98 per capsule 50 mg capsule |
| Shortage now | No current entry | 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