Drug Interaction Report

Gentamicin Topical and Tenofovir Alafenamide: Interaction Details

Name: Gentamicin Topical and Tenofovir Alafenamide Interaction
Creator: Dr. Brian Staiger, PharmD, BCPS

A pharmacist-reviewed analysis of the Gentamicin Topical and Tenofovir Alafenamide 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

Gentamicin Topical

Garamycin®

Tenofovir Alafenamide

No brand names on record

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 75 documented Gentamicin Topical interactions, 36 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

Increased tenofovir alafenamide exposure and an increased risk of tenofovir alafenamide-related adverse effects

Interaction Deep Dive

Coadministration of tenofovir alafenamide with drugs that are eliminated by active tubular secretion such as aminoglycosides may increase tenofovir alafenamide exposure resulting in increased risk of tenofovir alafenamide-related adverse reactions¹².

Why it happens (mechanism)

Reduced renal function or compete for active tubular secretion

Common questions

Can I take Gentamicin Topical and Tenofovir Alafenamide together?

Increased tenofovir alafenamide exposure and an increased risk of tenofovir alafenamide-related adverse effects Always confirm with your pharmacist or prescriber before making any change.

How serious is the Gentamicin Topical and Tenofovir Alafenamide 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 Gentamicin Topical or Tenofovir Alafenamide 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 (2)

Product Information: DESCOVY(R) oral tablets, emtricitabine tenofovir alafenamide oral tablets. Gilead Sciences Inc (per FDA), Foster City, CA, 2025. DailyMed
Product Information: SYMTUZA(R) oral tablets, darunavir, cobicistat, emtricitabine, tenofovir alafenamide oral tablets. Janssen Products, LP (per FDA), Horsham, PA, 2023. DailyMed

Was this write-up helpful?

Gentamicin Topical

Keep reading about Gentamicin Topical

All Gentamicin Topical interactions (75) Gentamicin Topical drug information

Also serious with: Ataluren Agalsidase Alfa Alcuronium Aspirin

Tenofovir Alafenamide

Keep reading about Tenofovir Alafenamide

All Tenofovir Alafenamide interactions (67)

Also serious with: Acyclovir Naproxen Aspirin Capmatinib

Check another combination

Our instant two-drug interaction checker is almost here.

Coming soon

The instant two-drug checker is on its way.

In the meantime, browse the directory below to look up any drug and see its documented interactions.

Still have questions about this combination?

Every question gets a real answer from a licensed pharmacist — free, and usually within a day.

Ask the pharmacist

A message from HelloPharmacist

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.