Estradiol and Tizanidine Interaction

Drug interaction information between Estradiol and Tizanidine.

Estradiol and Tizanidine have a documented minor interaction in FDA labeling.

FDA drug labeling documents a minor-severity interaction between Estradiol and Tizanidine. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.

Drug A

Estradiol

Estrogen Hormone

Drug B

Tizanidine

Central Alpha-2 Agonist (Muscle Relaxant)

How They Interact

Estradiol can stop your body from breaking down tizanidine as fast as it should. This can cause the tizanidine levels to build up in your blood.

FDA Label Information

Concomitant use with ethinyl estradiol-containing COCs may increase systemic exposure of other drugs (e.g., cyclosporine, prednisolone, theophylline, tizanidine, and voriconazole).

Frequently Asked Questions

What SPL severity band is on file for Estradiol + Tizanidine?

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?

Estradiol has 54 labeled pairs on file vs Tizanidine's 17. In the minor band specifically: Estradiol has 50 (also Rosuvastatin, Lamotrigine, Topiramate, Acetaminophen); Tizanidine has 14 (also Acyclovir, Verapamil, Amiodarone, Propafenone).

What mechanism field is on file for Estradiol and Tizanidine?

Estradiol can stop your body from breaking down tizanidine as fast as it should. This can cause the tizanidine levels to build up in your blood.

Tizanidine carries more major-labeled pairs than Estradiol

SPL source-record counts only. This page's band is minor · classes on file: Estradiol (Estrogen Hormone); Tizanidine (Central Alpha-2 Agonist (Muscle Relaxant)).

Tizanidine has 2 major-labeled pairs vs Estradiol's 1. This page itself is in the minor band, not the major band.

Estradiol

1 major · 3 moderate · 50 minor · 54 total

Tizanidine

2 major · 1 moderate · 14 minor · 17 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.