Fluvoxamine and Tizanidine Interaction
Drug interaction information between Fluvoxamine and Tizanidine.
Fluvoxamine and Tizanidine have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Fluvoxamine and Tizanidine. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Fluvoxamine blocks the enzyme that normally clears tizanidine from your body. This leads to much higher amounts of tizanidine in your blood than intended.
What To Do
This combination should not be used. Your doctor will need to change one of your medications to a safer option.
FDA Label Information
( 7.2 , 12.3 ) 7.1 Strong CYP1A2 Inhibitors Concomitant use of tizanidine with strong cytochrome P450 1A2 (CYP1A2) inhibitors (e.g., fluvoxamine, ciprofloxacin) is contraindicated.
Fluvoxamine Also Interacts With
- Lithium moderate
- Phenelzine moderate
- Tasimelteon moderate
- Metoprolol minor
- Omeprazole minor
Tizanidine Also Interacts With
- Ciprofloxacin major
- Famotidine moderate
- Acyclovir minor
- Verapamil minor
- Amiodarone minor
Frequently Asked Questions
Can I take Fluvoxamine and Tizanidine together?
This is a major interaction. This combination should not be used. Your doctor will need to change one of your medications to a safer option.
How serious is the interaction between Fluvoxamine and Tizanidine?
This interaction is classified as "major" severity by the FDA. Major interactions may be life-threatening or cause serious side effects.
Why do Fluvoxamine and Tizanidine interact?
Fluvoxamine blocks the enzyme that normally clears tizanidine from your body. This leads to much higher amounts of tizanidine in your blood than intended.
Understanding the Fluvoxamine and Tizanidine Interaction
FDA-approved prescribing information for these two drugs flags their combination as a major-severity interaction. Fluvoxamine belongs to the Selective Serotonin Reuptake Inhibitor (SSRI) class and Tizanidine belongs to the Central Alpha-2 Agonist (Muscle Relaxant) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Fluvoxamine blocks the enzyme that normally clears tizanidine from your body. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Fluvoxamine has 40 total documented interactions on file in this dataset, and Tizanidine has 17. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: This combination should not be used. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Fluvoxamine or Tizanidine based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.