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Tasimelteon and Fluvoxamine Interaction

Drug interaction information between Tasimelteon and Fluvoxamine.

Tasimelteon and Fluvoxamine have a documented moderate interaction in FDA labeling.

FDA drug labeling documents a moderate-severity interaction between Tasimelteon and Fluvoxamine. 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.

Drug A

Tasimelteon

Melatonin Receptor Agonist

Drug B

Fluvoxamine

Selective Serotonin Reuptake Inhibitor (SSRI)

How They Interact

Fluvoxamine blocks the enzyme that normally breaks down tasimelteon. This causes tasimelteon to build up in your body, which increases the risk of side effects.

What To Do

Do not take these two medications at the same time. Your doctor should find an alternative treatment to avoid high drug levels.

FDA Label Information

7 DRUG INTERACTIONS Strong CYP1A2 inhibitors (e.g., fluvoxamine): Avoid use of tasimelteon in combination with strong CYP1A2 inhibitors because of increased exposure ( 7.1 , 12.3 ) Strong CYP3A4 inducers (e.g., rifampin): Avoid use of tasimelteon in combination with rifampin or other CYP3A4 inducers, because of decreased exposure ( 7.2 , 12.3 ) 7.1 Strong CYP1A2 Inhibitors (e.g., fluvoxamine) Avoid use of tasimelteon in combination with fluvoxamine or other strong CYP1A2 inhibitors because of a potentially large increase in tasimelteon exposure and greater risk of adverse reactions [see...

Frequently Asked Questions

Can I take Tasimelteon and Fluvoxamine together?

This is a moderate interaction. Do not take these two medications at the same time. Your doctor should find an alternative treatment to avoid high drug levels.

How serious is the interaction between Tasimelteon and Fluvoxamine?

This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.

Why do Tasimelteon and Fluvoxamine interact?

Fluvoxamine blocks the enzyme that normally breaks down tasimelteon. This causes tasimelteon to build up in your body, which increases the risk of side effects.

Understanding the Tasimelteon and Fluvoxamine Interaction

FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Tasimelteon belongs to the Melatonin Receptor Agonist class and Fluvoxamine belongs to the Selective Serotonin Reuptake Inhibitor (SSRI) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Fluvoxamine blocks the enzyme that normally breaks down tasimelteon. 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. Tasimelteon has 5 total documented interactions on file in this dataset, and Fluvoxamine has 40. 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: Do not take these two medications at the same time. 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 Tasimelteon or Fluvoxamine 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.