What the FDA labels say about taking them together
Lithium and theophylline
Theophylline's FDA label of March 10, 2026 names lithium in its drug interactions section; the lithium labels PlainMeds reads (4) do not name theophylline. The theophylline label: “May lower theophylline seizure threshold Lithium Theophylline increases renal lithium clearance.”
Check it at the source: the lithium FDA label on DailyMed (effective December 23, 2025, Glenmark Pharmaceuticals Inc., USA); the theophylline FDA label on DailyMed (effective March 10, 2026, Strides Pharma Science Limited).
What does the lithium label say about theophylline?
Lithium's label (effective December 23, 2025) and its 3 other brand-application labels do not name theophylline 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 theophylline label say about lithium?
Theophylline label, drug interactionsMay lower theophylline seizure threshold Lithium Theophylline increases renal lithium clearance.
Source: FDA drug label (Theophylline), Strides Pharma Science Limited, effective March 10, 2026 (SPL set b7a90ccf-9c32-40cc-9008-7e55b3da4dfd), 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 | Theophylline | |
|---|---|---|
| Labeled for | Bipolar disorder | Asthma |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.104 per capsule 300 mg capsule | $0.330 per tablet 300 mg tablet |
| 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