Famotidine and Tizanidine Interaction
Drug interaction information between Famotidine and Tizanidine.
Famotidine and Tizanidine have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Famotidine 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.
How They Interact
Famotidine can slow down the body's ability to clear tizanidine, which may lead to dangerously high levels of the drug in your blood.
FDA Label Information
( 7.1 ) • Tizanidine (CYP1A2) Substrate: Potential for substantial increases in blood concentrations of tizanidine resulting in hypotension, bradycardia or excessive drowsiness; avoid concomitant use, if possible. 7.2 Tizanidine (CYP1A2 Substrate) Although not studied clinically, famotidine is considered a weak CYP1A2 inhibitor and may lead to substantial increases in blood concentrations of tizanidine, a CYP1A2 substrate. Refer to the full prescribing information for tizanidine.
Famotidine Also Interacts With
- Theophylline major
- Ketoconazole minor
- Ledipasvir/Sofosbuvir minor
- Itraconazole minor
- Aripiprazole minor
Tizanidine Also Interacts With
- Ciprofloxacin major
- Fluvoxamine major
- Acyclovir minor
- Verapamil minor
- Amiodarone minor
Frequently Asked Questions
What SPL severity band is on file for Famotidine + Tizanidine?
Compiled FDA labeling labels this pair moderate. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Tizanidine has 17 labeled pairs on file vs Famotidine's 11. In the moderate band specifically: Famotidine has 1; Tizanidine has 1.
What mechanism field is on file for Famotidine and Tizanidine?
Famotidine can slow down the body's ability to clear tizanidine, which may lead to dangerously high levels of the drug in your blood.
Tizanidine carries more major-labeled pairs than Famotidine
SPL source-record counts only. This page's band is moderate · classes on file: Famotidine (H2 Receptor Antagonist); Tizanidine (Central Alpha-2 Agonist (Muscle Relaxant)).
Tizanidine has 2 major-labeled pairs vs Famotidine's 1. This page itself is in the moderate band, not the major band.
1 major · 1 moderate · 9 minor · 11 total
Famotidine has no other moderate-band peer in this dataset besides Tizanidine.
2 major · 1 moderate · 14 minor · 17 total
Tizanidine has no other moderate-band peer in this dataset besides Famotidine.
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.