What the FDA labels say about taking them together
Levothyroxine and sucralfate
Levothyroxine's FDA label of February 20, 2024 names sucralfate in its drug interactions section; the sucralfate labels PlainMeds reads (2) do not name levothyroxine. The levothyroxine label: “… Calcium Carbonate Cation Exchange Resins - Kayexalate Ferrous Sulfate Orlistat Sucralfate; Effect: Concurrent use may reduce the efficacy of levothyroxine by binding and delaying or preventing absorption, potentially …”
Check it at the source: the levothyroxine FDA label on DailyMed (effective February 20, 2024, AbbVie Inc.); the sucralfate FDA label on DailyMed (effective September 2, 2026, Preferred Pharmaceuticals Inc.).
What does the levothyroxine label say about sucralfate?
Levothyroxine label, drug interactionsProton Pump Inhibitors Sucralfate Antacids (e.g., aluminum & magnesium hydroxides, simethicone) Gastric acidity is an essential requirement for adequate absorption of levothyroxine.
Levothyroxine Sodium label (Amneal Pharmaceuticals NY LLC, December 6, 2024), drug interactionsDrug or Drug Class: Antacids - Aluminum & Magnesium Hydroxides - Simethicone Bile Acid Sequestrants - Cholestyramine - Colestipol Calcium Carbonate Cation Exchange Resins - Kayexalate Ferrous Sulfate Orlistat Sucralfate; Effect: Concurrent use may reduce the efficacy of levothyroxine by binding and delaying or preventing absorption, potentially resulting in hypothyroidism. Calcium carbonate may form an insoluble chelate with levothyroxine, and ferrous sulfate likely forms a ferric-thyroxine complex. Administer levothyroxine at least 4 hours apart from these agents. Patients treated concomitantly with orlistat and levothyroxine should be monitored for changes in thyroid function.
Source: FDA drug label (Levothyroxine Sodium, NDA021210), Amneal Pharmaceuticals NY LLC, effective December 6, 2024 (SPL set fca88c97-5cd4-4834-ba87-deb5bd637788), via openFDA
Source: FDA drug label (Levoxyl, NDA021301), Pfizer Laboratories Div Pfizer Inc, effective December 15, 2020 (SPL set 758588c3-c63e-491b-0aa2-4f50d80cb174), via openFDA
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 sucralfate label say about levothyroxine?
Sucralfate's label (effective September 2, 2026) and its 1 other brand-application label do not name levothyroxine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Sucralfate), NDA018333 (Abbvie), as published by Preferred Pharmaceuticals Inc., effective September 2, 2026 (SPL set 536b8c00-13ab-4397-a754-63a1c92bf883), 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 | Sucralfate | |
|---|---|---|
| Labeled for | Hypothyroidism | Acid reflux and ulcers |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.0588 per tablet 112 mcg tablet | $0.173 per tablet 1 g 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