Drug & supplement interaction

Coffee Charcoal + Voxelotor

Voxelotor brand name: Oxbryta.

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

Coffee Charcoal has a moderate interaction with Voxelotor. Coffee charcoal can reduce the absorption of orally administered drugs and should be separated from oral drug administration by at least two hours.

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

Coffee Charcoal and Voxelotor

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

Moderate

ORAL DRUGS

Why this applies to Voxelotor

Voxelotor falls under ORAL DRUGS — the group Coffee Charcoal interacts with.

Coffee charcoal can reduce the absorption of orally administered drugs and should be separated from oral drug administration by at least two hours.
Severity Moderate Likelihood Probable Evidence D

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 gist with coffee charcoal and Oxbryta (voxelotor): charcoal-type materials are porous and can grab onto medicines sitting in your stomach and intestines. If that happens, your body may absorb less of your voxelotor dose. The concern here is a weaker effect, meaning your hemoglobin may not hold onto oxygen as well and your red blood cells may not be protected the way they should be.

This is a theoretical concern based on how charcoal behaves, not something proven with voxelotor specifically, so don't panic. A simple fix is timing: keep them well apart, ideally taking voxelotor at least two hours away from the coffee charcoal. Since voxelotor is taken once daily for a serious condition, please run your routine by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.

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

Coffee Charcoal Also Interacts With Other Medications

Coffee Charcoal has 2,021 moderate known drug interactions in our database — the Voxelotor one above is one of them. If you take anything else, check it against the full list below.

Moderate 2,021 No known interaction 809 (incl. Voxelotor)
Taking anything else?

Check Another of Your Medications Against Coffee Charcoal

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

Everything else you take

See Every Supplement That Interacts With Voxelotor

This page covers Coffee Charcoal only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Voxelotor page lists 143 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).

By severity: 3 major · 100 moderate · 40 minor.

From our pharmacist’s overview on the Voxelotor page

“Anyone taking voxelotor (Oxbryta) for sickle cell disease should treat this list with real care, because the pattern behind it is unusually consistent. Almost every entry works through CYP3A4, the same liver enzyme that clears voxelotor, so these ingredients can push the drug's blood level higher or pull it lower, either adding side ef…”

Reviewed by 2 · Jul 18, 2026

Open the Voxelotor interaction page

How much people look this up

Where Coffee Charcoal and Voxelotor 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 Coffee Charcoal
Top half

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

29 days ago today
Medication Voxelotor
Steady interest

#2,825 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 Coffee Charcoal

What is Coffee Charcoal?

  • Diarrhea
  • Inflammatory bowel conditions
  • Irritable bowel syndrome (IBS)
  • Mild digestive upset
  • Wound and skin care (topical, traditional)

Coffee charcoal is made by roasting green coffee beans until they turn black, creating a charcoal-like material used traditionally for diarrhea and digestive complaints. Scientific evidence supporting its benefits is very limited, and it should not replace proven treatments. Talk with your pharmacist or doctor before using it, especially if you have a chronic gut condition.

Read the full Coffee Charcoal monograph & all interactions
Medication

About Voxelotor

What Is Voxelotor Used For?

Brand name: Oxbryta

Oxbryta (voxelotor) is approved to treat sickle cell disease (SCD) in adults and in children as young as 4 years old. It works by targeting the underlying problem in sickle cell disease — the abnormal hemoglobin that causes red blood cells to take on a rigid, sickle shape.

This approval was granted under the FDA's accelerated approval pathway, based on the drug's ability to raise hemoglobin levels. Continued approval may depend on results from confirmatory clinical trials showing broader clinical benefit.

See full Voxelotor drug information
Keep checking

Other Drugs & Coffee Charcoal

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

0Major
2,021Moderate
0Minor
808No known interaction
2,021 Moderate 808 No interaction
Moderate

2,021 interactions

Showing 60 of 2,021 moderate interactions — see all 2,021 on the Coffee Charcoal page.

No interaction 808 drugs checked — show the list

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

Showing the 60 most looked-up of 808 medications checked with no known interaction — see the full Coffee Charcoal list.

See the full Coffee Charcoal interactions page
See every supplement checked against Voxelotor, 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
Coffee Charcoal monograph › Uses, safety, and every drug interaction in one place Voxelotor supplement interactions › Every supplement checked against Voxelotor, ranked by severity Voxelotor 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 Coffee Charcoal and Voxelotor Together: Common Questions

Can you take Coffee Charcoal with Voxelotor?
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 Coffee Charcoal and Voxelotor 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 Voxelotor and Coffee Charcoal?

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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.