Heparin and Levothyroxine Interaction
Drug interaction information between Heparin and Levothyroxine.
Heparin and Levothyroxine have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Heparin and Levothyroxine. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Heparin can push the thyroid medicine off the proteins it normally hitches a ride on in your blood.
FDA Label Information
Other drugs: Carbamazepine Furosemide (> 80 mg IV) Heparin Hydantoins Non-Steroidal Anti-inflammatory Drugs - Fenamates These drugs may cause protein-binding site displacement. Other drugs: Carbamazepine Furosemide (> 80 mg IV) Heparin Hydantoins Non-Steroidal Anti-inflammatory Drugs - Fenamates These drugs may cause protein-binding site displacement.
Heparin Also Interacts With
- Ibuprofen moderate
- Celecoxib moderate
- Hydroxychloroquine moderate
- Indomethacin moderate
- Dipyridamole moderate
Levothyroxine Also Interacts With
- Sertraline minor
- Furosemide minor
- Propranolol minor
- Ferrous Sulfate minor
- Amitriptyline minor
Frequently Asked Questions
What SPL severity band is on file for Heparin + Levothyroxine?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Levothyroxine has 22 labeled pairs on file vs Heparin's 20. In the minor band specifically: Heparin has 10 (also Nitroglycerin, Amlodipine/Valsartan, Liothyronine, Oritavancin); Levothyroxine has 22 (also Sertraline, Furosemide, Propranolol, Ferrous Sulfate).
What mechanism field is on file for Heparin and Levothyroxine?
Heparin can push the thyroid medicine off the proteins it normally hitches a ride on in your blood.
Levothyroxine's labeled portfolio outnumbers Heparin
SPL source-record counts only. This page's band is minor · classes on file: Heparin (Unfractionated Heparin); Levothyroxine (Thyroid Hormone).
0 major · 10 moderate · 10 minor · 20 total
- Other minor peers for Heparin
- Nitroglycerin
- Amlodipine/Valsartan
- Liothyronine
- Oritavancin
0 major · 0 moderate · 22 minor · 22 total
- Other minor peers for Levothyroxine
- Sertraline
- Furosemide
- Propranolol
- Ferrous Sulfate
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.