Drug & supplement interaction

Coca + Doxazosin Mesylate

Doxazosin Mesylate brand name: Cardura.

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

Coca has a moderate interaction with Doxazosin Mesylate. Theoretically, coca might reduce the effects of antihypertensive drugs.

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

Coca and Doxazosin Mesylate

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Doxazosin Mesylate

Doxazosin Mesylate falls under ANTIHYPERTENSIVE DRUGS — the group Coca interacts with.

Theoretically, coca might reduce the effects of antihypertensive drugs.
Some clinical research suggests that coca and the coca constituent cocaine have hypertensive effects. Theoretically, concomitant use of coca with antihypertensive drugs might interfere with blood pressure control and decrease the effectiveness of antihypertensive drugs.
Severity Moderate Likelihood Probable Evidence B

Interaction 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..

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

Here's the simple version: doxazosin works by relaxing your blood vessels and the muscles around your prostate, which brings your blood pressure down and makes urinating easier. Coca leaves contain cocaine and related stimulant compounds, and those can actually raise blood pressure and tighten blood vessels. So the two are working in opposite directions.

If you used coca while taking doxazosin, it could partly cancel out the medicine, meaning your blood pressure might not stay controlled and your BPH symptoms could feel less managed. To be fair, this is mostly theoretical and based on lower-quality research, so the real-world risk isn't fully proven. Still, coca is a controlled substance and not a safe supplement. Please check with your pharmacist or doctor before mixing anything like this.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Favier R, Caceres E, Guillon L, et al. Coca chewing for exercise: hormonal and metabolic responses of nonhabitual chewers. J Appl Physiol 1996;81:1901-7.. PubMed
  2. Favier R, Caceres E, Sempore B, et al. Fluid regulatory hormone response to exercise after coca-induced body fluid shifts. J Appl Physiol 1997;83:376-82.. PubMed
  3. Spielvogel H, Rodriguez A, Sempore B, et al. Body fluid homeostasis and cardiovascular adjustments during submaximal exercise: influence of chewing coca leaves. Eur J Appl Physiol Occup Physiol 1997;75(5):400-6. PubMed
  4. Spielvogel, H., Caceres, E., Koubi, H., Sempore, B., Sauvain, M., and Favier, R. Effects of coca chewing on metabolic and hormonal changes during graded incremental exercise to maximum. J.Appl.Physiol 1996;80(2):643-649. 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

Coca Also Interacts With Other Medications

Coca has 2 major, 256 moderate known drug interactions in our database — the Doxazosin Mesylate one above is one of them. If you take anything else, check it against the full list below.

Major 2 Moderate 256 No known interaction 2,572 (incl. Doxazosin Mesylate)
Taking anything else?

Check Another of Your Medications Against Coca

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

From our Q&A

Questions About Coca or Doxazosin Mesylate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Coca or Doxazosin Mesylate, 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 Doxazosin Mesylate

This page covers Coca only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Doxazosin Mesylate page lists 137 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), Tyramine (major) and Adrafinil (moderate).

By severity: 4 major · 112 moderate · 21 minor.

From our pharmacist’s overview on the Doxazosin Mesylate page

“Doxazosin (Cardura) relaxes blood vessels to lower blood pressure and ease enlarged-prostate symptoms, and it already has a reputation for dizziness and first-dose fainting. That is why its list of 137 interacting supplements deserves genuine respect.”

Reviewed by 2 · Jul 18, 2026

Open the Doxazosin Mesylate interaction page

How much people look this up

Where Coca and Doxazosin Mesylate 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 Coca
Steady interest

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

29 days ago today
Medication Doxazosin Mesylate
Top half

#855 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 Coca

What is Coca?

Coca
  • Altitude sickness
  • Fatigue and low energy
  • Appetite and hunger suppression
  • Digestive upset
  • Flavoring agent in foods and drinks

Coca is a South American plant best known as the natural source of cocaine. While the leaves have a long history of traditional use for altitude sickness, fatigue, and hunger, the whole plant contains cocaine and other alkaloids that make it legally controlled and potentially dangerous in most countries. Only decocainized (cocaine-free) coca extract is used in foods, and there is little reliable evidence to recommend coca as a supplement.

Read the full Coca monograph & all interactions
Medication

About Doxazosin

What Is Doxazosin Used For?

Brand name: Cardura

Doxazosin tablets (Cardura, Doxazosin, Doxazosin mesylate) are approved to treat the signs and symptoms of benign prostatic hyperplasia (BPH) — an enlarged prostate that causes urinary problems — and to treat high blood pressure (hypertension). Lowering blood pressure reduces the risk of stroke and heart attack. Doxazosin tablets may be used alone or combined with other blood pressure medicines.

Cardura XL (the extended-release tablet) is approved only for BPH symptoms. Cardura XL is not approved for high blood pressure.

See full Doxazosin drug information
Keep checking

Other Drugs & Coca

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

2Major
256Moderate
0Minor
2,571No known interaction
2 Major 256 Moderate 2,571 No interaction
Major

2 interactions

Moderate

256 interactions

Showing 60 of 256 moderate interactions — see all 256 on the Coca page.

No interaction 2,571 drugs checked — show the list

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

Showing the 60 most looked-up of 2,571 medications checked with no known interaction — see the full Coca list.

See the full Coca interactions page
See every supplement checked against Doxazosin Mesylate, 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
Coca monograph › Uses, safety, and every drug interaction in one place Doxazosin Mesylate supplement interactions › Every supplement checked against Doxazosin Mesylate, ranked by severity Doxazosin 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

Taking Coca and Doxazosin Mesylate Together: Common Questions

Can you take Coca with Doxazosin Mesylate?
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 Coca and Doxazosin Mesylate 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 Doxazosin Mesylate and Coca?

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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.