Drug & supplement interaction

Light Therapy + Diclofenac Potassium

Diclofenac Potassium brand names: Voltaren Rapide, Cataflam, Cataflam IR, Voltarol Rapid, Cambia.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Light Therapy has a moderate interaction with Diclofenac Potassium. Light therapy may increase the risk for photosensitization.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
Know someone interested in this? Share
Facebook Post Reddit Email
On this page
Interaction report

Light Therapy and Diclofenac Potassium

Here is the interaction we found between these two, with the evidence behind it.

Moderate

PHOTOSENSITIZING DRUGS

Why this applies to Diclofenac Potassium

Diclofenac Potassium falls under PHOTOSENSITIZING DRUGS — the group Light Therapy interacts with.

Light therapy may increase the risk for photosensitization.
Concomitant use of photosensitizing drugs with light therapy may increase the risk for phototoxicity and should be avoided.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the connection to know about. Diclofenac (the active ingredient in Cataflam and Voltaren) belongs to a group of medicines that can make your skin more sensitive to light, a reaction we call photosensitivity. Since light therapy involves sitting in front of bright light on purpose, pairing the two could, in theory, raise your chances of a skin reaction like redness, a rash, or an exaggerated sunburn-type response on exposed skin.

I want to be honest about how strong this concern is. This is a theoretical caution based on how the drug works, not on a flood of real-world reports, so for many people it never becomes a problem. Still, it's worth a quick chat with your pharmacist or doctor before combining them, especially if you notice your skin reacting more than usual.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Pathirana, D., Ormerod, A. D., Saiag, P., Smith, C., Spuls, P. I., Nast, A., Barker, J., Bos, J. D., Burmester, G. R., Chimenti, S., Dubertret, L., Eberlein, B., Erdmann, R., Ferguson, J., Girolomoni, G., Gisondi, P., Giunta, A., Griffiths, C., Honigsmann
  2. Leon, A., Nguyen, A., Letsinger, J., and Koo, J. An attempt to formulate an evidence-based strategy in the management of moderate-to-severe psoriasis: a review of the efficacy and safety of biologics and prebiologic options. Expert Opin Pharmacother 2007; PubMed
  3. Morgan, M. and Khan, D. A. Therapeutic alternatives for chronic urticaria: an evidence-based review, Part 2. Ann Allergy Asthma Immunol 2008;100(6):517-526. PubMed
  4. Hoare, C., Li Wan, Po A., and Williams, H. Systematic review of treatments for atopic eczema. Health Technol Assess 2000;4(37):1-191. DOI
  5. Whitton, M. E., Pinart, M., Batchelor, J., Lushey, C., Leonardi-Bee, J., and Gonzalez, U. Interventions for vitiligo. Cochrane Database Syst Rev 2010;(1):CD003263. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Light Therapy Also Interacts With Other Medications

Light Therapy has 334 moderate known drug interactions in our database — the Diclofenac Potassium one above is one of them. If you take anything else, check it against the full list below.

Moderate 334 No known interaction 2,496 (incl. Diclofenac Potassium)
Taking anything else?

Check Another of Your Medications Against Light Therapy

Covers the 2,830 medications we’ve checked against Light Therapy. Pick one to open its full report.

From our Q&A

Questions About Light Therapy or Diclofenac Potassium

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Light Therapy or Diclofenac Potassium, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Diclofenac Potassium

This page covers Light Therapy only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diclofenac Potassium page lists 306 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Danshen (major) and Piracetam (major).

Open the Diclofenac Potassium interaction page

How much people look this up

Where Light Therapy and Diclofenac Potassium Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Light Therapy
Top half

#618 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Diclofenac Potassium
Top half

#1,142 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Treatment approach

About Light Therapy

What is Light Therapy?

  • Seasonal affective disorder (SAD)
  • Non-seasonal depression
  • Sleep and circadian rhythm problems
  • Jet lag and shift-work sleep issues
  • Certain skin conditions

Light therapy uses controlled exposure to bright artificial light and is best supported for seasonal affective disorder, where it is a recognized treatment option. It is generally safe for most people when used as directed, but you should talk to a doctor or pharmacist first, especially if you have eye conditions, bipolar disorder, or take medicines that increase light sensitivity.

Read the full Light Therapy monograph & all interactions
Medication

About Diclofenac

What Is Diclofenac Used For?

Brand names: Voltaren Rapide, Cataflam, Cataflam IR, Voltarol Rapid, Cambia

Diclofenac sodium topical gel is used to treat actinic keratoses (AK) — rough, scaly skin patches that form after years of sun exposure. These patches are considered precancerous, meaning they can develop into skin cancer if left untreated.

This is a topical gel, meaning it is applied directly to the skin over the affected area rather than taken by mouth. It belongs to the NSAID (nonsteroidal anti-inflammatory drug) family.

See full Diclofenac drug information
Keep checking

Other Drugs & Light Therapy

Browse every other medication we’ve checked against Light Therapy — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
334Moderate
0Minor
2,495No known interaction
334 Moderate 2,495 No interaction
Moderate

334 interactions

Showing 60 of 334 moderate interactions — see all 334 on the Light Therapy page.

No interaction 2,495 drugs checked — show the list

We also checked Light Therapy against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,495 medications checked with no known interaction — see the full Light Therapy list.

See the full Light Therapy interactions page
See every supplement checked against Diclofenac Potassium, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Light Therapy monograph › Uses, safety, and every drug interaction in one place Diclofenac Potassium supplement interactions › Every supplement checked against Diclofenac Potassium, ranked by severity Diclofenac drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Having Light Therapy While Taking Diclofenac Potassium: Common Questions

Can you have Light Therapy while taking Diclofenac Potassium?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Light Therapy and Diclofenac Potassium interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Diclofenac Potassium and Light Therapy?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.