Levothyroxine and Propranolol Interaction
Drug interaction information between Levothyroxine and Propranolol.
Levothyroxine and Propranolol have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Levothyroxine and Propranolol. 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
Taking large doses of this blood pressure medicine can change the levels of thyroid hormones in your blood. However, it usually does not change how your thyroid actually functions or how you feel.
FDA Label Information
Drug or Drug Class Effect Beta-adrenergic antagonists (e.g., Propranolol > 160 mg/day) In patients treated with large doses of propranolol (> 160 mg/day), T3 and T4 levels change, TSH levels remain normal, and patients are clinically euthyroid. Drug or Drug Class Effect Beta-adrenergic antagonists (e.g., Propranolol > 160 mg/day) In patients treated with large doses of propranolol (> 160 mg/day), T3 and T4 levels change, TSH levels remain normal, and patients are clinically euthyroid.
Levothyroxine Also Interacts With
- Sertraline minor
- Furosemide minor
- Ferrous Sulfate minor
- Amitriptyline minor
- Carbamazepine minor
Frequently Asked Questions
What SPL severity band is on file for Levothyroxine + Propranolol?
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?
Propranolol has 44 labeled pairs on file vs Levothyroxine's 22. In the minor band specifically: Levothyroxine has 22 (also Sertraline, Furosemide, Ferrous Sulfate, Amitriptyline); Propranolol has 44 (also Clonidine, Diltiazem, Warfarin, Verapamil).
What mechanism field is on file for Levothyroxine and Propranolol?
Taking large doses of this blood pressure medicine can change the levels of thyroid hormones in your blood. However, it usually does not change how your thyroid actually functions or how you feel.
Propranolol's labeled portfolio outnumbers Levothyroxine
SPL source-record counts only. This page's band is minor · classes on file: Levothyroxine (Thyroid Hormone); Propranolol (Non-Selective Beta-Blocker).
0 major · 0 moderate · 22 minor · 22 total
- Other minor peers for Levothyroxine
- Sertraline
- Furosemide
- Ferrous Sulfate
- Amitriptyline
0 major · 0 moderate · 44 minor · 44 total
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.