Drug & supplement interaction

Coenzyme Q10 + Hydrochlorothiazide, Valsartan

Hydrochlorothiazide, Valsartan brand name: Diovan HCT.

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

Coenzyme Q10 has a minor interaction with Hydrochlorothiazide, Valsartan. Theoretically, coenzyme Q10 might have additive effects with antihypertensive drugs.

Read the full interaction report
SeverityMinor
LikelihoodPossible
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Coenzyme Q10 and Hydrochlorothiazide, Valsartan

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

Minor

ANTIHYPERTENSIVE DRUGS

Why this applies to Hydrochlorothiazide, Valsartan

Hydrochlorothiazide, Valsartan falls under ANTIHYPERTENSIVE DRUGS — the group Coenzyme Q10 interacts with.

Theoretically, coenzyme Q10 might have additive effects with antihypertensive drugs.
Some clinical research shows that coenzyme Q10 can significantly lower blood pressure, although other studies have shown conflicting results.
Severity Minor Likelihood Possible Evidence B

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 simple version: your Diovan HCT (valsartan plus hydrochlorothiazide) is a two-part blood pressure medicine. The valsartan relaxes your blood vessels, and the water pill (hydrochlorothiazide) helps your body shed extra fluid and salt. CoQ10 has its own mild blood-pressure-lowering tendency, so taking the two together could nudge your numbers a little lower than the medicine alone.

For most folks this is a minor effect, and the research behind it is mixed and not very strong. Still, if your readings run low, watch for dizziness, lightheadedness when you stand up, or feeling unusually tired. Don't change anything on your own. Just give your pharmacist or doctor a heads-up before you add CoQ10 so they can keep an eye on your blood pressure.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Langsjoen P, Willis R, Folkers K. Treatment of essential hypertension with coenzyme Q10. Mol Aspects Med 1994;S265-72. PubMed
  2. Singh RB, Niaz MA, Rastogi SS, et al. Effect of hydrosoluble coenzyme Q10 on blood pressures and insulin resistance in hypertensive patients with coronary artery disease. J Hum Hypertens 1999;13:203-8. PubMed
  3. Burke BE, Neuenschwander R, Olson RD. Randomized, double-blind, placebo-controlled trial of coenzyme Q10 in isolated systolic hypertension. South Med J 2001;94:1112-7. PubMed
  4. Hodgson JM, Watts GF, Playford DA, et al. Coenzyme Q10 improves blood pressure and glycaemic control: a controlled trial in subjects with type 2 diabetes. Eur J Clin Nutr 2002;56:1137-42. PubMed
  5. Digiesi V, Cantini F, Oradei A, et al. Coenzyme Q10 in essential hypertension. Mol Aspects Med 1994;15 Suppl:s257-63. PubMed
  6. Yamagami T, Takagi M, Akagami H, et al. Effect of coenzyme Q10 on essential hypertension, a double blind controlled study. In: Folkers KA, Yamamura Y, eds. Biomedical and Clinical Aspects of Coenzyme Q, Vol. 5. Amsterdam: Elsevier Science Publications, 19
  7. Ho MJ, Bellusci A, Wright JM. Blood pressure lowering efficacy of coenzyme Q10 for primary hypertension (review). Cochrane Database Syst Rev 2009;(4):CD007435. PubMed
  8. Young, J. M., Florkowski, C. M., Molyneux, S. L., McEwan, R. G., Frampton, C. M., Nicholls, M. G., Scott, R. S., and George, P. M. A randomized, double-blind, placebo-controlled crossover study of coenzyme Q10 therapy in hypertensive patients with the me
  9. Digiesi V, Cantini F, and Brodbeck B. Effect of coenzyme Q10 on essential arterial hypertension. Current Therapeutic Research 1990;47(5):841-845.
  10. Ho MJ, Li EC, Wright JM. Blood pressure lowering efficacy of coenzyme Q10 for primary hypertension. Cochrane Database Syst Rev. 2016 Mar 3;3:CD007435. doi: 10.1002/14651858.CD007435.pub3. PubMed
  11. Tabrizi R, Akbari M, Sharifi N, Lankarani KB, Moosazadeh M, Kolahdooz F, et al. The effects of coenzyme Q10 supplementation on blood pressures among patients with metabolic diseases: a systematic review and meta-analysis of randomized controlled trials. 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

Coenzyme Q10 Also Interacts With Other Medications

Coenzyme Q10 has 26 moderate, 171 minor known drug interactions in our database — the Hydrochlorothiazide, Valsartan one above is one of them. If you take anything else, check it against the full list below.

Moderate 26 Minor 171 No known interaction 2,633 (incl. Hydrochlorothiazide, Valsartan)
Taking anything else?

Check Another of Your Medications Against Coenzyme Q10

Covers the 2,830 medications we’ve checked against Coenzyme Q10. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Hydrochlorothiazide, Valsartan

This page covers Coenzyme Q10 only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Hydrochlorothiazide, Valsartan page lists 273 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Asarabacca (major) and Dolomite (major).

By severity: 10 major · 226 moderate · 37 minor.

From our pharmacist’s overview on the Hydrochlorothiazide, Valsartan page

“Diovan HCT pairs valsartan with the water pill hydrochlorothiazide to bring blood pressure down, and the 273 supplements listed here deserve genuine care, ten of them rated major. Most of the moderate entries either drop blood pressure further than intended or blunt the medication, and a second large group compounds the diuretic action…”

Reviewed by 2 · Jul 18, 2026

Open the Hydrochlorothiazide, Valsartan interaction page

One more smart check

Taking Coenzyme Q10 as Part of a Dietary Supplement Product? Check It for Interactions

We hold 6,926 real supplement products containing Coenzyme Q10, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Coenzyme Q10. Your product may carry other ingredients that interact with Hydrochlorothiazide, Valsartan too, on top of Coenzyme Q10 — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Coenzyme Q10 and Hydrochlorothiazide, Valsartan 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 Coenzyme Q10
Top 5%

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

29 days ago today
Medication Hydrochlorothiazide, Valsartan
Top 25%

#483 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.

Supplement

About Coenzyme Q10

What is Coenzyme Q10?

  • Heart health
  • Statin-related muscle aches
  • Migraine prevention
  • Energy and fatigue
  • Aging and antioxidant support

CoQ10 is a vitamin-like substance your body makes naturally that helps cells produce energy and acts as an antioxidant. It is generally well tolerated and is most studied for heart conditions, statin-related muscle symptoms, and migraine prevention, though the strength of the evidence varies. Talk with your pharmacist or doctor before starting it, especially if you take heart or blood pressure medicines.

Read the full Coenzyme Q10 monograph & all interactions
Keep checking

Other Drugs & Coenzyme Q10

Browse every other medication we’ve checked against Coenzyme Q10 — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
26Moderate
171Minor
2,632No known interaction
26 Moderate 171 Minor 2,632 No interaction
Moderate

26 interactions

Minor

171 interactions

Showing 60 of 171 minor interactions — see all 171 on the Coenzyme Q10 page.

No interaction 2,632 drugs checked — show the list

We also checked Coenzyme Q10 against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,632 medications checked with no known interaction — see the full Coenzyme Q10 list.

See the full Coenzyme Q10 interactions page
See every supplement checked against Hydrochlorothiazide, Valsartan, 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
Coenzyme Q10 monograph › Uses, safety, and every drug interaction in one place Hydrochlorothiazide, Valsartan supplement interactions › Every supplement checked against Hydrochlorothiazide, Valsartan, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Coenzyme Q10 and Hydrochlorothiazide, Valsartan Together: Common Questions

Can you take Coenzyme Q10 with Hydrochlorothiazide, Valsartan?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Coenzyme Q10 and Hydrochlorothiazide, Valsartan interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Hydrochlorothiazide, Valsartan and Coenzyme Q10?

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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.