Drug & supplement interaction

Coca + Methyldopa

Methyldopa brand names: Aldomet, Methyldopa.

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

Coca has a moderate interaction with Methyldopa. 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 Methyldopa

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

Moderate

ANTIHYPERTENSIVE DRUGS

Why this applies to Methyldopa

Methyldopa 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: Coca works against what your methyldopa is trying to do. Methyldopa lowers your blood pressure by relaxing your blood vessels and calming the nerve signals that tighten them. Coca leaves contain cocaine and related stimulant compounds that do the opposite, they can rev up your nervous system and push your blood pressure and heart rate up.

So if you use coca while taking methyldopa, your pressure may not stay controlled, and you could see numbers creeping back up. The evidence here is on the weaker side and partly theoretical, but the direction is pretty clear. Keep in mind whole coca is also legally controlled in most places. If you're considering it, please talk with your pharmacist or doctor first rather than changing anything on your own.

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 Methyldopa 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. Methyldopa)
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 Methyldopa

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 Methyldopa, 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 Methyldopa

This page covers Coca only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Methyldopa page lists 173 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), Beer (major) and Cowhage (major).

By severity: 8 major · 144 moderate · 21 minor.

From our pharmacist’s overview on the Methyldopa page

“Alcohol is the entry I would read first. Methyldopa (Aldomet) can be hard on the liver by itself, and 38 of the 173 supplement and herbal ingredients here, beer and wine included, carry liver risks that could stack on top of that.”

Reviewed by 2 · Jul 18, 2026

Open the Methyldopa interaction page

How much people look this up

Where Coca and Methyldopa 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

#1,205 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Methyldopa
Steady interest

#1,778 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 Methyldopa

What Is Methyldopa Used For?

Brand names: Aldomet, Methyldopa

Methyldopa tablets are used to treat high blood pressure (hypertension) in adults and children. Lowering blood pressure reduces the risk of complications that come with uncontrolled hypertension.

See full Methyldopa 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 Methyldopa, 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 Methyldopa supplement interactions › Every supplement checked against Methyldopa, ranked by severity Methyldopa 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 Methyldopa Together: Common Questions

Can you take Coca with Methyldopa?
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 Methyldopa 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 Methyldopa 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.