Drug & supplement interaction

Light Therapy + Gemcitabine

Gemcitabine brand name: Gemzar.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated July 2026 · Pair last verified Sep 20, 2026

The bottom line No known interaction

We found no known interaction between Light Therapy and Gemcitabine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Light Therapy and Gemcitabine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Gemcitabine and Light Therapy in our sources. This does not guarantee that the combination is completely free of risk — research on Light Therapy alongside specific medications may be limited.

Light Therapy is a treatment rather than something you take. Tell whoever provides it which medicines you use, and ask your prescriber whether it is appropriate for your health and treatment. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Light Therapy safety at a glance

Light Therapy overall Use caution Generally well tolerated, but certain eye, skin, and mood conditions need medical guidance.

Pregnancy Possibly Safe When bright light therapy is used short-term. Other types of light therapies, especially PUVA, have not been extensively evaluated in pregnancy or lactation. On... Read the full pregnancy detail

Breastfeeding Possibly Safe When bright light therapy is used short-term. Other types of light therapies, especially PUVA, have not been extensively evaluated in pregnancy or lactation. On... Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Gemcitabine and Light Therapy? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Gemcitabine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Gemcitabine is filed under 2 classifications — antineoplastics, hepatotoxic drugs. Light Therapy has documented interactions with 1 drug class — the most serious being photosensitizing drugs (moderate) — and none of Gemcitabine’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Light Therapy Does Interact With Other Medications

Light Therapy has 335 moderate known drug interactions in our database — Gemcitabine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 335 No known interaction 2,495 (incl. Gemcitabine)

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.

What to actually watch for

No Interaction Found — But Data Suggests Light Therapy and Gemcitabine May Share a Side Effect

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so having Light Therapy while taking the medicine can make those effects more likely to turn up, and harder to pin on one or the other if they do.

Nausea reported in 4.9% of FDA reports for Gemcitabine Additional detail
Light Therapy
“Nausea is a commonly reported side effect of light therapy. Changes in appetite, dry mouth, diarrhea, constipation, and abdominal pain have also been reported.”

Light Therapy · Natural Medicines adverse-effect record, reported in constipation.
3 sources cited

28938. 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

28979. Terman, M. and Terman, J. S. Bright light therapy: side effects and benefits across the symptom spectrum. J Clin Psychiatry 1999;60(11):799-808. DOI

106586. Nussbaumer-Streit B, Thaler K, Chapman A, et al. Second-generation antidepressants for treatment of seasonal affective disorder. Cochrane Database Syst Rev 2021;3(3):CD008591. PubMed
Gemcitabine

Listed in the ADVERSE REACTIONS section of the FDA label for Gemcitabine, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Light Therapy but not commonly for Gemcitabine: a change in sex drive, blurred vision, stomach pain and eye irritation or redness.

Effects for Gemcitabine come from the ADVERSE REACTIONS section of its FDA label; effects for Light Therapy come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 53,020 voluntary FDA FAERS reports for Gemcitabine that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Light Therapy in Pregnancy & Breastfeeding

Pregnancy And Lactation Possibly Safe

When bright light therapy is used short-term. Other types of light therapies, especially PUVA, have not been extensively evaluated in pregnancy or lactation. One preliminary study suggests that PUVA use does not result in teratogenic effects. Until more information is available, avoid use in those who are pregnant and lactating.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Everything else you take

See Every Supplement That Interacts With Gemcitabine

This page covers Light Therapy only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Gemcitabine page lists 39 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Beer (major), Siberian Cocklebur (major), Wine (major), Ashwagandha (moderate) and Black Cohosh (moderate).

By severity: 3 major · 35 moderate · 1 minor.

Open the Gemcitabine interaction page

How much people look this up

Where Light Therapy and Gemcitabine 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

Steady interest

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

29 days ago today

Medication Gemcitabine

Steady interest

#2,588 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.

Where does our data come from?

Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Light Therapy reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Light Therapy and Gemcitabine records this page draws on were last updated July 10, 2026.
What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.

Data structure & sourcing designed and verified by Dr. Brian Staiger, PharmD, BCPS.

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.

Not applicable (light exposure, not a plant) · Light boxes, dawn-simulating alarm clocks, light visors, wearable light devices, blue/red light panels

An interaction check asks whether these two react with each other — it does not ask whether Light Therapy is a good idea for someone in your situation. Here is what our Light Therapy record says about it on its own.

Light Therapy: dosing

There is no single dose that fits everyone, and the right approach depends on the device and the reason you are using it. For seasonal affective disorder, a common general approach involves a 10,000-lux light box used for a set time in the morning, sitting a recommended distance from the light with eyes open but not staring at it.Because brightness, distance, and timing all matter, follow the instructions that come with your specific device. They can help you pick the right device and schedule.

From our Light Therapy monograph — the full record covers uses, side effects and every documented interaction.

Read the full Light Therapy monograph & all interactions

Medication

About Gemcitabine Injection

What Is Gemcitabine Injection Used For?

Brand name: Gemzar

Gemcitabine Injection (available as Avgemsi, Gemcitabine, and Infugem) is used to treat several types of cancer. It is given in combination with carboplatin for advanced ovarian cancer that has returned at least 6 months after platinum-based treatment, and in combination with paclitaxel as a first-line treatment for metastatic breast cancer after prior chemotherapy with an anthracycline (a specific class of chemo drug).

It is also given in combination with cisplatin for non-small cell lung cancer (NSCLC) that cannot be removed surgically or has spread. For pancreatic cancer that is locally advanced or has spread, it is used as a single agent — including in patients who have already been treated with fluorouracil.

Most-Reported Side Effects for Gemcitabine

From FAERS, the FDA’s public side-effect reporting system (53,020 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Disease progression 4,850 reports

Thrombocytopenia 3,706 reports

Neutropenia 3,295 reports

Anemia 3,084 reports

Malignant neoplasm progression 2,912 reports

See full Gemcitabine Injection 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

335Moderate

0Minor

2,494No known interaction

335 Moderate 2,494 No interaction

Moderate

335 interactions

Showing 60 of 335 moderate interactions — see all 335 on the Light Therapy page.

No interaction 2,494 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 2,494 medications checked with no known interaction — see the full Light Therapy list.

See the full Light Therapy interactions page

See every supplement checked against Gemcitabine, ranked by severity

Evidence & sources

Light Therapy References

The 35 references that drive our Light Therapy monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

Meduri, N. B., Vandergriff, T., Rasmussen, H., and Jacobe, H. Phototherapy in the management of atopic dermatitis: a systematic review. Photodermatol Photoimmunol Photomed 2007;23(4):106-112. PubMed
Kumar, P., Chawla, D., and Deorari, A. Light-emitting diode phototherapy for unconjugated hyperbilirubinaemia in neonates. Cochrane Database Syst Rev 2011;(12):CD007969. PubMed
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
Beani, J. C. and Jeanmougin, M. [Narrow-band UVB therapy in psoriasis vulgaris: good practice guideline and recommendations of the French Society of Photodermatology]. Ann Dermatol Venereol 2010;137(1):21-31.
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
Kroft, E. B., Berkhof, N. J., van de Kerkhof, P. C., Gerritsen, R. M., and de Jong, E. M. Ultraviolet A phototherapy for sclerotic skin diseases: a systematic review. J Am Acad Dermatol 2008;59(6):1017-1030. PubMed
Tuunainen, A., Kripke, D. F., and Endo, T. Light therapy for non-seasonal depression. Cochrane Database Syst Rev 2004;(2):CD004050. DOI
Chesson, A. L., Jr., Littner, M., Davila, D., Anderson, W. M., Grigg-Damberger, M., Hartse, K., Johnson, S., and Wise, M. Practice parameters for the use of light therapy in the treatment of sleep disorders. Standards of Practice Committee, American Acade DOI
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
Lee, E., Koo, J., and Berger, T. UVB phototherapy and skin cancer risk: a review of the literature. Int J Dermatol 2005;44(5):355-360. PubMed
Murase, J. E., Lee, E. E., and Koo, J. Effect of ethnicity on the risk of developing nonmelanoma skin cancer following long-term PUVA therapy. Int J Dermatol 2005;44(12):1016-1021. PubMed
Morison, W. L., Baughman, R. D., Day, R. M., Forbes, P. D., Hoenigsmann, H., Krueger, G. G., Lebwohl, M., Lew, R., Naldi, L., Parrish, J. A., Piepkorn, M., Stern, R. S., Weinstein, G. D., and Whitmore, S. E. Consensus workshop on the toxic effects of long
Stern, R. S. The risk of squamous cell and basal cell cancer associated with psoralen and ultraviolet A therapy: a 30-year prospective study. J Am Acad Dermatol 2012;66(4):553-562. PubMed
Stern, R. S. and Lunder, E. J. Risk of squamous cell carcinoma and methoxsalen (psoralen) and UV-A radiation (PUVA). A meta-analysis. Arch Dermatol 1998;134(12):1582-1585. PubMed
Swerdlow, A. J. and Weinstock, M. A. Do tanning lamps cause melanoma? An epidemiologic assessment. J Am Acad Dermatol 1998;38(1):89-98. PubMed
Terman, M. and Terman, J. S. Bright light therapy: side effects and benefits across the symptom spectrum. J Clin Psychiatry 1999;60(11):799-808. DOI
Westrin, A. and Lam, R. W. Seasonal affective disorder: a clinical update. Ann Clin Psychiatry 2007;19(4):239-246. PubMed
Stern, R. S. and Lange, R. Outcomes of pregnancies among women and partners of men with a history of exposure to methoxsalen photochemotherapy (PUVA) for the treatment of psoriasis. Arch Dermatol 1991;127(3):347-350. DOI
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
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
Bedair K, Elhadad A, Hamad S, Ferguson J, Donnan P, Dawe RS. No association between whole-body ultraviolet A1 phototherapy and skin cancers in humans: a cancer registry linkage study. Br J Dermatol. 2020;183(3):586-7. PubMed
Nussbaumer-Streit B, Thaler K, Chapman A, et al. Second-generation antidepressants for treatment of seasonal affective disorder. Cochrane Database Syst Rev 2021;3(3):CD008591. PubMed
Ju HJ, Han JH, Kim MS, et al. The long-term risk of lymphoma and skin cancer did not increase after topical calcineurin inhibitor use and phototherapy in a cohort of 25,694 patients with vitiligo. J Am Acad Dermatol 2021;84(6):1619-1627.
Ko MJ, Huang JW, Wu HY, et al. Risk of Skin Cancer among Patients with Chronic Kidney Disease Treated with Ultraviolet B Phototherapy for Uraemic Pruritus: A Nationwide Cohort Study. Acta Derm Venereol 2021;101(2):adv00390. PubMed
Donmez M, Yorguner N, Kora K, Topcuoglu V. Efficacy of bright light therapy in perinatal depression: A randomized, double-blind, placebo-controlled study. J Psychiatr Res 2022;149:315-322. PubMed
Bugaiski-Shaked A, Shany E, Mesner O, Sergienko R, Wainstock T. Association between neonatal phototherapy exposure and childhood neoplasm. J Pediatr 2022;245:111-116. PubMed
Wu YH, Chou CL, Chang HC. Risk of skin cancer after ultraviolet phototherapy in patients with vitiligo: a systematic review and meta-analysis. Clin Exp Dermatol 2022;47(4):692-699. PubMed
Sun W, Yan J, Wu J, Ma H. Efficacy and safety of light therapy as a home treatment for motor and non-motor symptoms of Parkinson disease: A meta-analysis. Med Sci Monit 2022;28:e935074. PubMed
Zhu S, Ma X, Ding X, et al. Comparative evaluation of low-level light therapy and ethinyl estradiol and desogestrel combined oral contraceptive for clinical efficacy and regulation of serum biochemical parameters in primary dysmenorrhoea: a prospective ra
Ravindran S, Pai B S, Shetty VM. Risk of cutaneous carcinogenesis with phototherapy in Indian subpopulation: A 10-year analysis and a review of literature. Dermatol Ther 2022;35(7):e15536. PubMed
Ahad T, Wang EY, Liu YA, et al. Incidence of skin cancers in patients with eczema treated with ultraviolet phototherapy. J Am Acad Dermatol 2022;87(2):387-389. PubMed
Abdellatif M, Tawfik GM, Makram AM, et al. Association between neonatal phototherapy and future cancer: an updated systematic review and meta-analysis. Eur J Pediatr 2023;182(1):329-341. PubMed
Agaoglu E, Erdogan HK, Acer E, Saracoglu ZN, Bilgin M. Narrowband ultraviolet B phototherapy for pityriasis lichenoides: A real-life experience. Photodermatol Photoimmunol Photomed 2023;39(5):520-526. PubMed
Hotta M, Ueda K, Ikehara S, et al. Phototherapy and risk of developmental delay: the Japan Environment and Children's Study. Eur J Pediatr 2023;182(5):2139-2149. PubMed
Hotta M, Ueda K, Ikehara S, et al. The Duration of Neonatal Phototherapy and Allergic Disorders: The Japan Environment and Children's Study. Int Arch Allergy Immunol 2023;184(3):211-219. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Having Light Therapy While Taking Gemcitabine: Common Questions

Is it safe to have Light Therapy while taking Gemcitabine?

We do not list a known interaction between Light Therapy and Gemcitabine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.

Do Light Therapy and Gemcitabine have any of the same side effects?

Yes — our sources link each of them separately to one of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.

How was the Light Therapy and Gemcitabine combination checked?

Interactions in our licensed database are recorded against drug classes. Gemcitabine is filed under 2 classifications, and Light Therapy has documented interactions with 1 drug class — none of Gemcitabine's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.

Does Light Therapy interact with any other medications?

Yes. Light Therapy has 335 documented drug interactions in our database — Gemcitabine is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

Does Gemcitabine interact with any supplements?

Yes. Gemcitabine has documented interactions with 39 supplements in our database — Light Therapy is not one of them. The Gemcitabine interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Light Therapy monograph Uses, safety profile, and every drug interaction in one place Gemcitabine Injection drug information The full plain-English guide to this medication Gemcitabine supplement interactions Every supplement checked against Gemcitabine, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 35 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Gemcitabine and Light Therapy?

Our pharmacists answer your medication & supplement questions — free.

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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.