What the FDA labels say about taking them together
Levothyroxine and sevelamer
Levothyroxine's FDA label of February 20, 2024 names sevelamer in its drug interactions section, and sevelamer's label names levothyroxine too.
Check it at the source: the levothyroxine FDA label on DailyMed (effective February 20, 2024, AbbVie Inc.); the sevelamer FDA label on DailyMed (effective November 25, 2025, Sanofi-Aventis U.S. LLC).
What does the levothyroxine label say about sevelamer?
Levothyroxine label, drug interactionsDrug or Drug Class Effect Phosphate Binders (e.g., calcium carbonate, ferrous sulfate, sevelamer, lanthanum) Phosphate binders may bind to levothyroxine.
Source: FDA drug label (Synthroid), AbbVie Inc., effective February 20, 2024 (SPL set 1e11ad30-1041-4520-10b0-8f9d30d30fcc), via openFDA; the full label on DailyMed
What does the sevelamer label say about levothyroxine?
Sevelamer label, drug interactionsFor oral medication where a reduction in the bioavailability of that medication would have a clinically significant effect on its safety or efficacy (e.g., cyclosporine, tacrolimus, levothyroxine), consider separation of the timing of the administration of the two drugs [see Clinical Pharmacology (12.3) ].
Source: FDA drug label (Sevelamer Carbonate), Sanofi-Aventis U.S. LLC, effective November 25, 2025 (SPL set 3abc32fe-1bfc-4759-8f7c-36095e221b06), 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
| Levothyroxine | Sevelamer | |
|---|---|---|
| Labeled for | Hypothyroidism | n/a |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.0588 per tablet 112 mcg tablet | $0.214 per tablet 800 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