Levothyroxine and Amitriptyline Interaction
Drug interaction information between Levothyroxine and Amitriptyline.
Levothyroxine and Amitriptyline have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Levothyroxine and Amitriptyline. 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
Using these drugs together can make your body more sensitive to certain chemicals, which may increase the side effects of both medications.
FDA Label Information
7.5 Antidepressant Therapy Concurrent use of tricyclic (e.g., amitriptyline) or tetracyclic (e.g., maprotiline) antidepressants and levothyroxine sodium may increase the therapeutic and toxic effects of both drugs, possibly due to increased receptor sensitivity to catecholamines. 7.5 Antidepressant Therapy Concurrent use of tricyclic (e.g., amitriptyline) or tetracyclic (e.g., maprotiline) antidepressants and levothyroxine sodium may increase the therapeutic and toxic effects of both drugs, possibly due to increased receptor sensitivity to catecholamines.
Levothyroxine Also Interacts With
- Sertraline minor
- Furosemide minor
- Propranolol minor
- Ferrous Sulfate minor
- Carbamazepine minor
Amitriptyline Also Interacts With
- Risperidone major
- Sertraline minor
- Fluoxetine minor
- Paroxetine minor
- Disulfiram minor
Frequently Asked Questions
What SPL severity band is on file for Levothyroxine + Amitriptyline?
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 Amitriptyline's 21. In the minor band specifically: Levothyroxine has 22 (also Sertraline, Furosemide, Propranolol, Ferrous Sulfate); Amitriptyline has 20 (also Sertraline, Fluoxetine, Paroxetine, Disulfiram).
What mechanism field is on file for Levothyroxine and Amitriptyline?
Using these drugs together can make your body more sensitive to certain chemicals, which may increase the side effects of both medications.
Amitriptyline carries more major-labeled pairs than Levothyroxine
SPL source-record counts only. This page's band is minor · classes on file: Levothyroxine (Thyroid Hormone); Amitriptyline (Tricyclic Antidepressant (TCA)).
Amitriptyline has 1 major-labeled pair vs Levothyroxine's 0. This page itself is in the minor band, not the major band.
0 major · 0 moderate · 22 minor · 22 total
- Other minor peers for Levothyroxine
- Sertraline
- Furosemide
- Propranolol
- Ferrous Sulfate
1 major · 0 moderate · 20 minor · 21 total
- Other minor peers for Amitriptyline
- Sertraline
- Fluoxetine
- Paroxetine
- Disulfiram
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.