Drug Interaction Report

Lumacaftor and Dexamethasone Injection: Interaction Details

Name: Lumacaftor and Dexamethasone Injection Interaction
Creator: Dr. Brian Staiger, PharmD, BCPS

A pharmacist-reviewed analysis of the Lumacaftor and Dexamethasone Injection interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Lumacaftor

No brand names on record

Dexamethasone Injection

Decadron Dexasone Dexium Dextenza Dexycu Hemady Maxidex Ozurdex

Medically reviewed by

Dr. Brian Staiger, PharmD, BCPS

Updated Aug 8, 2026

Editorial policy · Data sources

Interaction severity

Major

Potentially serious — often needs a change or close monitoring.

Minor

Moderate

Major

Contraindicated

How we grade severity & evidence

Severity levels

Contraindicated: These should generally not be used together.
Major: Potentially serious — often needs a change or close monitoring.
Moderate: Can be significant — usually manageable with monitoring.
Minor: Usually limited clinical impact.

Evidence grades

Established: Well documented — supported by controlled studies or strong clinical data.
Probable: Good supporting evidence, though not definitively proven.
Suspected: Some evidence suggests this interaction, but it is not well established.
Possible: Limited or conflicting evidence; the interaction may occur.
Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 97 documented Lumacaftor interactions, 88 are rated major — including this one.

Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.

Onset

unspecified

Evidence

theoretical

Severity

Major

What happens

Reduced dexAMETHasone exposure

Interaction Deep Dive

Coadministration of strong CYP3A4 inducers may decrease dexAMETHasone exposure, which may result in loss of efficacy. Consider alternative medications that are not strong CYP3A4 inducers. If concomitant use of strong CYP3A4 inducers with dexAMETHasone cannot be avoided, closely monitor for adverse drug reactions¹.

Why it happens (mechanism)

Induction of CYP3A4-mediated metabolism of dexAMETHasone

Common questions

Can I take Lumacaftor and Dexamethasone Injection together?

Reduced dexAMETHasone exposure Always confirm with your pharmacist or prescriber before making any change.

How serious is the Lumacaftor and Dexamethasone Injection interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

Does my dose of Lumacaftor or Dexamethasone Injection need adjusting while I take them together?
What symptoms should prompt me to call you or my prescriber right away?
Does the timing of my doses matter for this combination?
Is there a safer alternative to one of these medications for me?

References (1)

Product Information: HEMADY(TM) oral tablets, dexamethasone oral tablets. Dexcel Pharma Technologies (per FDA), Boulder, CO, 2019. DailyMed

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Lumacaftor

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All Lumacaftor interactions (97)

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Dexamethasone Injection

Keep reading about Dexamethasone Injection

All Dexamethasone Injection interactions (308) Dexamethasone Injection drug information

Also serious with: Mifepristone Praziquantel Ranolazine Rilpivirine

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About our interaction database: depth, not breadth

HelloPharmacist doesn't license one of the big commercial interaction databases, so what you'll find here is not a complete list of every known drug interaction. Instead, each entry is researched, analyzed, and written up individually — documented from the published literature, reviewed by a pharmacist, and cited so you can check every source yourself.

If a combination isn't listed here, it means we haven't documented it yet — never that it's safe. For screening a full medication list, we recommend pairing this site with a comprehensive tool like the Drugs.com Interaction Checker and, most importantly, a review by your own pharmacist. For a deep, plain-English, fully sourced explanation of a specific documented interaction — that's exactly what we built this for.

This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.