Drug & supplement interaction

Cocoa + Hydralazine, Hydrochlorothiazide, Reserpine

Hydralazine, Hydrochlorothiazide, Reserpine brand names: Ser-Ap-Es, Unipres, Uniserp.

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

Hydralazine, Hydrochlorothiazide, Reserpine falls into 2 drug categories that Cocoa can interact with; the most serious is rated moderate. Theoretically, taking cocoa with antihypertensive drugs might increase the risk of hypotension.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Cocoa and Hydralazine, Hydrochlorothiazide, Reserpine

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Cocoa interacts with whole categories of medication. Hydralazine, Hydrochlorothiazide, Reserpine falls into 2 of those categories, so it can interact with Cocoa in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ANTIHYPERTENSIVE DRUGS

1 of 2

Why this applies to Hydralazine, Hydrochlorothiazide, Reserpine

Hydralazine, Hydrochlorothiazide, Reserpine falls under ANTIHYPERTENSIVE DRUGS — the group Cocoa interacts with.

Theoretically, taking cocoa with antihypertensive drugs might increase the risk of hypotension.
Clinical research shows that cocoa can modestly decrease blood pressure in hypertensive and normotensive patients.
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

This combination pill packs a triple punch for blood pressure: hydralazine relaxes your blood vessels, hydrochlorothiazide (a water pill) lowers fluid, and reserpine calms nerve signals that tighten vessels. Cocoa's flavanols may gently help blood vessels widen too, so in theory it could nudge your blood pressure a little lower on top of what your medicine already does.

This concern is theoretical, based on how things work rather than reported problems, and the effect from cocoa is usually mild. A cup of hot cocoa or a piece of dark chocolate is unlikely to cause trouble. Concentrated cocoa supplements are a different story. If you notice dizziness, lightheadedness when standing, or feeling faint, check in with your pharmacist or doctor before changing anything.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Taubert D, Berkels R, Roesen R, Klaus W. Chocolate and blood pressure in elderly individuals with isolated systolic hypertension. JAMA 2003;290:1029-30.. PubMed
  2. Grassi D, Necozione S, Lippi C, et al. Cocoa reduces blood pressure and insulin resistance and improves endothelium-dependent vasodilation in hypertensives. Hypertension 2005;46:398-405. PubMed
  3. Taubert D, Roesen R, Schomig E. Effect of cocoa and tea intake on blood pressure: a meta-analysis. Arch Intern Med 2007;167:626-34. PubMed
  4. Taubert D, Roesen R, Lehmann C, et al. Effects of low habitual cocoa intake on blood pressure and bioactive nitric oxide: a randomized controlled trial. JAMA 2007;298:49-60. PubMed
  5. Hooper L, Kay C, Abdelhamid A, et al. Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: a systematic review and meta-analysis of randomized trials. Am J Clin Nutr 2012;95:740-51. PubMed
  6. Hooper, L., Kroon, P. A., Rimm, E. B., Cohn, J. S., Harvey, I., Le Cornu, K. A., Ryder, J. J., Hall, W. L., and Cassidy, A. Flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials. Am J Clin Nutr 2008;88 PubMed
  7. Desch, S., Schmidt, J., Kobler, D., Sonnabend, M., Eitel, I., Sareban, M., Rahimi, K., Schuler, G., and Thiele, H. Effect of cocoa products on blood pressure: systematic review and meta-analysis. Am J Hypertens. 2010;23(1):97-103. PubMed
  8. Ried, K., Sullivan, T., Fakler, P., Frank, O. R., and Stocks, N. P. Does chocolate reduce blood pressure? A meta-analysis. BMC.Med 2010;8:39. PubMed
  9. Shrime, M. G., Bauer, S. R., McDonald, A. C., Chowdhury, N. H., Coltart, C. E., and Ding, E. L. Flavonoid-rich cocoa consumption affects multiple cardiovascular risk factors in a meta-analysis of short-term studies. J Nutr 2011;141(11):1982-1988. PubMed
  10. Sudarma, V., Sukmaniah, S., and Siregar, P. Effect of dark chocolate on nitric oxide serum levels and blood pressure in prehypertension subjects. Acta Med.Indones. 2011;43(4):224-228.
  11. Ried, K., Sullivan, T. R., Fakler, P., Frank, O. R., and Stocks, N. P. Effect of cocoa on blood pressure. Cochrane.Database.Syst.Rev. 2012;8:CD008893. PubMed
  12. Jafarnejad S, Salek M, Clark CCT. Cocoa consumption and blood pressure in middle-aged and elderly subjects: a meta-analysis. Curr Hypertens Rep. 2020;22(1):1. PubMed
  13. Balayssac-Siransy E, Ouattara S, Boka KJM, et al. Dose-effect relation between regular consumption of 100% cocoa powder and blood pressure in young, healthy black Africans. Physiol Rep 2021;9(20):e15070. PubMed
Moderate

DIURETIC DRUGS

2 of 2

Hydralazine, Hydrochlorothiazide, Reserpine also falls under DIURETIC DRUGS.

Theoretically, using cocoa with diuretic drugs might increase the risk of hypokalemia.
Cocoa contains caffeine. In excessive amounts, caffeine can reduce potassium levels due to stimulation of the sodium-potassium pump. Diuretics can also cause lower potassium levels.
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

This combination pill contains hydrochlorothiazide, a water pill that can lower your body's potassium over time. The concern here is theoretical: cocoa contains some caffeine, and in large amounts caffeine can nudge potassium out of the blood. Stacked on top of a diuretic, that could in theory drag potassium down a bit further.

Honestly, a normal cup of hot cocoa or a piece of chocolate is very unlikely to cause trouble. The worry is more about concentrated cocoa or caffeine supplements taken regularly. If potassium does drop too low, you might notice muscle cramps, weakness, fatigue, or an irregular heartbeat. Since this product also lowers blood pressure, watch for dizziness too. Talk with your pharmacist or doctor before adding cocoa supplements.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Norager, C. B., Jensen, M. B., Weimann, A., and Madsen, M. R. Metabolic effects of caffeine ingestion and physical work in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over study. Clin Endocrinol (Oxf) 2006;65(2):223-228. PubMed
  2. Simmonds, M. J., Minahan, C. L., and Sabapathy, S. Caffeine improves supramaximal cycling but not the rate of anaerobic energy release. Eur.J Appl Physiol 2010;109(2):287-295. PubMed
  3. Rigato, I., Blarasin, L., and Kette, F. Severe hypokalemia in 2 young bicycle riders due to massive caffeine intake. Clin J Sport Med. 2010;20(2):128-130. PubMed
  4. Ernest, D., Chia, M., and Corallo, C. E. Profound hypokalaemia due to Nurofen Plus and Red Bull misuse. Crit Care Resusc. 2010;12(2):109-110. DOI
  5. Clausen, T. Hormonal and pharmacological modification of plasma potassium homeostasis. Fundam.Clin Pharmacol 2010;24(5):595-605. 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

Cocoa Also Interacts With Other Medications

Cocoa has 634 moderate, 26 minor known drug interactions in our database — the Hydralazine, Hydrochlorothiazide, Reserpine one above is among them. If you take anything else, check it against the full list below.

Moderate 634 Minor 26 No known interaction 2,170 (incl. Hydralazine, Hydrochlorothiazide, Reserpine)
Taking anything else?

Check Another of Your Medications Against Cocoa

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

Everything else you take

See Every Supplement That Interacts With Hydralazine, Hydrochlorothiazide, Reserpine

This page covers Cocoa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Hydralazine, Hydrochlorothiazide, Reserpine page lists 231 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 · 196 moderate · 25 minor.

From our pharmacist’s overview on the Hydralazine, Hydrochlorothiazide, Reserpine page

“Ser-Ap-Es combines three blood pressure drugs, hydralazine, hydrochlorothiazide, and reserpine, so this list deserves real attention before you add a supplement. Most of the 231 ingredients on file either push blood pressure down further than intended or pile onto the diuretic and drag potassium and fluid levels with it.”

Reviewed by 2 · Jul 18, 2026

Open the Hydralazine, Hydrochlorothiazide, Reserpine interaction page

One more smart check

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

We hold 844 real supplement products containing Cocoa, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Cocoa. Your product may carry other ingredients that interact with Hydralazine, Hydrochlorothiazide, Reserpine too, on top of Cocoa — 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 Cocoa and Hydralazine, Hydrochlorothiazide, Reserpine 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 Cocoa
Top 25%

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

29 days ago today
Medication Hydralazine, Hydrochlorothiazide, Reserpine
Steady interest

#2,097 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 Cocoa

What is Cocoa?

Cocoa
  • Heart and blood vessel health
  • High blood pressure
  • High cholesterol
  • Mental focus and mood
  • Skin moisturizing (cocoa butter)

Cocoa is rich in plant compounds called flavanols that may modestly support blood vessel function and blood pressure, but most chocolate products are high in sugar, fat, and calories, which can offset any benefit. Enjoy cocoa as part of a balanced diet, and talk to your pharmacist before using concentrated cocoa supplements, especially if you have heart or blood pressure conditions.

Read the full Cocoa monograph & all interactions
Keep checking

Other Drugs & Cocoa

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

0Major
634Moderate
26Minor
2,169No known interaction
634 Moderate 26 Minor 2,169 No interaction
Moderate

634 interactions

Showing 60 of 634 moderate interactions — see all 634 on the Cocoa page.

Minor

26 interactions

No interaction 2,169 drugs checked — show the list

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

Showing the 60 most looked-up of 2,169 medications checked with no known interaction — see the full Cocoa list.

See the full Cocoa interactions page
See every supplement checked against Hydralazine, Hydrochlorothiazide, Reserpine, 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
Cocoa monograph › Uses, safety, and every drug interaction in one place Hydralazine, Hydrochlorothiazide, Reserpine supplement interactions › Every supplement checked against Hydralazine, Hydrochlorothiazide, Reserpine, 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 Cocoa and Hydralazine, Hydrochlorothiazide, Reserpine Together: Common Questions

Can you take Cocoa with Hydralazine, Hydrochlorothiazide, Reserpine?
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.
Why are there 2 interactions listed for Cocoa and Hydralazine, Hydrochlorothiazide, Reserpine?
Hydralazine, Hydrochlorothiazide, Reserpine belongs to more than one drug category, and Cocoa interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Cocoa and Hydralazine, Hydrochlorothiazide, Reserpine 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 Hydralazine, Hydrochlorothiazide, Reserpine and Cocoa?

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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.