Levothyroxine

214 interactions 1 explained in plain English 219 cited references

Also sold as: Ermeza Euthyrox Levo-T Levo-T® Levothroid® Levoxyl Levoxyl® Synthroid Synthroid® Thyquidity Thyro-Tabs Thyrocryn ThyroKare Tirosint Tirosint® Unithroid Unithroid®

About Levothyroxine

Levothyroxine is a hormone used to replace thyroid hormone and treat hypothyroidism and thyroid cancer. Read the full Levothyroxine drug information page →

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated Aug 10, 2026 · Editorial policy · Data sources

Sources: FDA prescribing information (Structured Product Labeling), the published literature cited in each entry, DDInter 2.0 (a major open-access drug-interaction database), and legacy DrugBank interaction data distributed by the NIH's RxNav service (decommissioned in 2024) — analyzed and reviewed by our pharmacist team. How we build this library →

Most serious with: Insulin Icodec-Abae Polystyrene Sulfonate Iomeprol Insulin Glargine, Recombinant Furosemide Epinephrine

17 Major 196 Moderate 1 Minor

All (214) Major (17) Moderate (196) Minor (1)

Major

Levothyroxine Digoxin Cardoxin® Reduced digoxin exposure Details Levothyroxine Furosemide Injection Disal Increased risk of free thyroid hormones, followed by an overall decrease in total thyroid hormone levels Details Levothyroxine Iomeprol Injection Reduced efficacy of thyroid therapy Details Levothyroxine Calcium Reduced levothyroxine absorption, reduced efficacy of levothyroxine and an increased risk of hypothyroidism Details Levothyroxine Calcium Carbonate Alka-Mints Reduced levothyroxine absorption, reduced efficacy of levothyroxine and an increased risk of hypothyroidism Details Levothyroxine Epinephrine Increased EPINEPHrine effects Details Levothyroxine Ferrous Sulfate Reduced efficacy of levothyroxine and an increased risk of hypothyroidism Details Levothyroxine Furosemide Disal Increased risk of free thyroid hormones, followed by an overall decrease in total thyroid hormone levels Details Levothyroxine Insulin Glargine, Recombinant Basaglar Reduced blood glucose lowering effect of insulin Details Levothyroxine Insulin Icodec-Abae Awiqli Reduced efficacy of insulin icodec-abae Details Levothyroxine Iomeprol Reduced efficacy of thyroid therapy Details Levothyroxine Iopromide Reduced efficacy of thyroid hormones Details Levothyroxine Iron Reduced efficacy of levothyroxine and an increased risk of hypothyroidism Details Levothyroxine Ketamine An increased risk of marked hypertension and tachycardia Details Levothyroxine Midodrine Orvaten® Increased risk of hypertension Details Levothyroxine Orlistat Alli Reduced efficacy of levothyroxine and an increased risk of hypothyroidism Details Levothyroxine Polystyrene Sulfonate Reduced efficacy of levothyroxine and an increased risk of hypothyroidism Details

Moderate

Levothyroxine Omeprazole Gastrobim Reduced efficacy of levothyroxine and an increased risk of hypothyroidism Details Levothyroxine Simvastatin Flolipid Explained Decreased levothyroxine efficacy Details Levothyroxine Acalabrutinib Calquence Increased risk of hypothyroidism Details Levothyroxine Acarbose Prandase® Worsening of glycemic control Details Levothyroxine Alectinib Alecensa Increased risk of hypothyroidism Details Levothyroxine Apixaban Eliquis Increased response to oral anticoagulant therapy Details Levothyroxine Asciminib Scemblix Increased risk of hypothyroidism Details Levothyroxine Avapritinib Ayvakit Increased risk of hypothyroidism Details Levothyroxine Afatinib Gilotrif Increased risk of hypothyroidism Details Levothyroxine Alogliptin Nesina Worsening of glycemic control Details Levothyroxine Axitinib Inlyta Increased risk of hypothyroidism Details Levothyroxine Baricitinib Olumiant Increased risk of hypothyroidism Details Levothyroxine Bosutinib Bosulif Increased risk of hypothyroidism Details Levothyroxine Brigatinib Alunbrig Increased risk of hypothyroidism Details Levothyroxine Cabozantinib Cabometyx Increased risk of hypothyroidism Details Levothyroxine Cabozantinib (Thyroid Cancer) Cabometyx Increased risk of hypothyroidism Details Levothyroxine Canagliflozin Invokana Worsening of glycemic control Details Levothyroxine Capmatinib Tabrecta Increased risk of hypothyroidism Details Levothyroxine Cholestyramine Resin Locholest® Reduced efficacy of levothyroxine and an increased risk of hypothyroidism Details Levothyroxine Colesevelam Welchol Reduced levothyroxine exposure and reduced efficacy of levothyroxine Details Levothyroxine Colestipol Colestid Reduced efficacy of levothyroxine and an increased risk of hypothyroidism Details Levothyroxine Dabigatran Pradaxa® Increased response to oral anticoagulant therapy Details Levothyroxine Dabigatran Etexilate Increased response to oral anticoagulant therapy Details

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