Medication interaction hub

What Supplements Interact with Dextromethorphan HBr?

Dextromethorphan HBr brand name: Vicks Formula 44 Cough Relief. Every interaction below applies to the brands too.

171 Interactions 4 Major 125 Moderate 42 Minor
Curated & coded by · Clinical Pharmacist · Updated September 22, 2026

Drug–supplement interaction data sourced from Natural Medicines Pro, the licensed clinical database from TRC Healthcare / Therapeutic Research, with additional analysis by the HelloPharmacist Pharmacist Team. Our sources · Editorial policy

What is this page for?

One answer, for one medication: what supplements and herbal products interact with Dextromethorphan HBr? Every vitamin, herb, and supplement ingredient we’ve checked against it is on this page, ranked by severity, each linking to the full report for that exact pair.

This page covers supplement interactions only — to check Dextromethorphan HBr against your other medications, use the drug–drug interaction checker. Educational information from our licensed clinical databases, not medical advice. Our editorial policy

HelloPharmacist Bottom Line
Our Pharmacist Explains
What is this? The interaction data in the HelloPharmacist supplement database is licensed from Natural Medicines Pro by TRC Healthcare (Therapeutic Research). HelloPharmacist pharmacists often add our own analysis and context on top of that licensed data — such as this Bottom Line summary and the notes on individual interaction pages — and any such commentary is noted as ours.

Dextromethorphan, the cough suppressant in Vicks Formula 44, feels too ordinary to worry about, yet this list warrants real care, and the four major entries among its 171 ingredients are the ones to understand first. Grapefruit and St. John's wort act on the liver enzyme that clears the drug, one raising its blood level and the other lowering it. Lithium can combine with dextromethorphan's serotonin activity to raise the risk of serotonin syndrome, a dangerous buildup of that brain chemical, and the fourth major blocks absorption.

Most of the 125 moderate entries repeat those themes more mildly: herbs that speed or slow the liver enzymes handling dextromethorphan, plus roughly twenty ingredients adding serotonin on top of the drug's own. A smaller group interferes with anything swallowed, so space those well apart from your dose. The remaining 42 rate minor, but the four majors are where I'd spend your reading time.

— , Clinical Pharmacist · July 18, 2026

Major 4 Moderate 125 Minor 42 No known interaction 1,281

This box checks one ingredient at a time (like turmeric or magnesium). Taking a supplement product with a whole label of ingredients? Search the product instead — we check every ingredient on it ↓

Top Ingredient Interactions

Dextromethorphan HBr: Top Interactions at a Glance

The most significant Dextromethorphan HBr supplement & herbal interactions, colored by severity. Tap any ingredient to open the full report for that pair.

Showing the 12 highest-ranked of 171 interacting ingredients — plus 1,281 more checked with no known interaction. See the complete ranked list.

Start here

The Major Interactions to Know About

The most clinically significant Dextromethorphan HBr + supplement combinations in our database, best-documented first. Open any card for the full report.

Major Likelihood Likely Grapefruit + Dextromethorphan HBri

Grapefruit juice can increase levels of drugs metabolized by CYP3A4.

Read the full interaction Major Likelihood Probable Activated Charcoal + Dextromethorphan HBri

Activated charcoal reduces systemic exposure to many drugs, including those that undergo enterohepatic recirculation, regardless of the route of administration.

Read the full interaction Major Likelihood Probable Lithium + Dextromethorphan HBri

Theoretically, taking lithium supplements with serotonergic drugs might both mask and increase the risk of serotonin syndrome.

Read the full interaction Major Likelihood Probable St. John's Wort + Dextromethorphan HBri

St.

Read the full interaction
The complete list

Every Supplement Checked Against Dextromethorphan HBr

All 1,452 ingredients in our database, ranked by severity — 171 with a Dextromethorphan HBr interaction on file and 1,281 with none found. Filter by severity or search any ingredient; hover the for what each ingredient is.

Looking for an interaction with a specific supplement product? Search products instead ↓

Straight answers

Can You Take It With Dextromethorphan HBr?

One-line answers, one card per combination — scroll through today’s 20 and tap any card for the full report. A different set rotates in daily until every combination has had its turn.

Can you take Ashwagandha with Dextromethorphan HBr?

Minor Usually — this is a minor-rated interaction, generally not clinically significant but worth mentioning to your pharmacist. Some animal studies have reported that ashwagandha can enhance serotonergic transmission by altering certain serotonin (5-HT) receptors.

Full Ashwagandha + Dextromethorphan HBr answer

Can you take Hawaiian Baby Woodrose with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, concomitant use may increase the risk for serotonergic adverse effects.

Full Hawaiian Baby Woodrose + Dextromethorphan HBr answer

Can you take African Wild Potato with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. In vitro evidence shows that African wild potato extract can inhibit cytochrome P450 3A4 (CYP3A4) enzyme activity by up to 86%.

Full African Wild Potato + Dextromethorphan HBr answer

Can you take American Elder with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking American elder might increase levels of CYP3A4 substrates.

Full American Elder + Dextromethorphan HBr answer

Can you take Astaxanthin with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, astaxanthin may decrease levels of drugs metabolized by CYP3A4.

Full Astaxanthin + Dextromethorphan HBr answer

Can you take Bacopa with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, bacopa might increase the levels and adverse effects of CYP3A4 substrates.

Full Bacopa + Dextromethorphan HBr answer

Can you take Beet with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, beet might increase the levels of CYP3A4 substrates.

Full Beet + Dextromethorphan HBr answer

Can you take Berberine with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, berberine might increase serum levels of drugs metabolized by CYP2D6.

Full Berberine + Dextromethorphan HBr answer

Can you take Beta-methylphenethylamine (bmpea) with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, BMPEA might increase the levels and clinical effects of CYP2D6 substrates.

Full Beta-methylphenethylamine (bmpea) + Dextromethorphan HBr answer

Can you take Bishop's Weed with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Bergapten, a constituent of bishop's weed, has been shown to inhibit cytochrome P450 3A4 (CYP3A4) in vitro.

Full Bishop's Weed + Dextromethorphan HBr answer

Can you take Bitter Orange with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Bitter orange might increase levels of drugs metabolized by CYP3A4.

Full Bitter Orange + Dextromethorphan HBr answer

Can you take Black Cohosh with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Some research suggests that black cohosh might inhibit CYP2D6, but there is conflicting evidence.

Full Black Cohosh + Dextromethorphan HBr answer

Can you take Black Pepper with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, black pepper might increase levels of drugs metabolized by CYP2D6.

Full Black Pepper + Dextromethorphan HBr answer

Can you take Black Seed with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, combining serotonergic drugs with black seed might increase the risk of serotonergic side effects, including serotonin syndro...

Full Black Seed + Dextromethorphan HBr answer

Can you take Bog Labrador Tea with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. In vitro research shows that aqueous and ethanolic extracts of Bog Labrador tea leaves can increase the concentration of cytochrome P450 3A4...

Full Bog Labrador Tea + Dextromethorphan HBr answer

Can you take Boswellia Serrata with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, Boswellia serrata might increase the levels of CYP2D6 substrates.

Full Boswellia Serrata + Dextromethorphan HBr answer

Can you take Bulbine Natalensis with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, Bulbine natalensis stem might reduce the levels and clinical effects of CYP3A4 substrates.

Full Bulbine Natalensis + Dextromethorphan HBr answer

Can you take Cajeput Oil with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Evidence from in vitro research suggests that cajeput leaf extract can inhibit cytochrome P450 2D6 (CYP2D6) by approximately 30%.

Full Cajeput Oil + Dextromethorphan HBr answer

Can you take Calamus with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, taking calamus with drugs metabolized by CYP2D6 might increase drug levels and potentially increase the risk of adverse effec...

Full Calamus + Dextromethorphan HBr answer

Can you take Cannabis with Dextromethorphan HBr?

Moderate Possibly, but carefully — this moderate-rated combination may need monitoring, a dose adjustment, or separated timing. Theoretically, cannabis may increase the levels and adverse effects of CYP3A4 substrates.

Full Cannabis + Dextromethorphan HBr answer
Read the list like a pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. 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.
  • Possible. 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
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each entry links to a full report with the clinical detail, likelihood, evidence level, and citations for that exact combination.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

How Does Our Interaction Checker Work?

Behind every verdict on this page is a category system. Our source database doesn’t document supplement interactions drug-by-drug — it documents them against groups of medications that behave the same way (for example, “drugs processed by the CYP3A4 liver enzyme” or “blood-thinning medications”).

So the check works in three steps: (1) Dextromethorphan HBr is classified into the pharmacology categories it belongs to, (2) every supplement interaction documented against any of those categories is inherited by Dextromethorphan HBr, and (3) each ingredient keeps its own severity, likelihood, and evidence grades from the underlying record. That’s why one supplement can carry several records for one drug — it may interact through more than one category.

Dextromethorphan HBr sits in 6 interaction categories. Open any one to see what the group means:

Cytochrome P450 3A4 (Cyp3A4) Substrates 121 ingredients

A drug-metabolism group: these medications are processed by the named liver enzyme (a cytochrome P450). Supplements that speed this enzyme up or slow it down can lower or raise the medication's levels in your body.

121 of the supplement ingredients on this page reach Dextromethorphan HBr through this category.

Cytochrome P450 2D6 (Cyp2D6) Substrates 60 ingredients

A drug-metabolism group: these medications are processed by the named liver enzyme (a cytochrome P450). Supplements that speed this enzyme up or slow it down can lower or raise the medication's levels in your body.

60 of the supplement ingredients on this page reach Dextromethorphan HBr through this category.

Serotonergic Drugs 20 ingredients

Medications that raise serotonin activity. Combining them with serotonin-active supplements can, in rare cases, push serotonin too high.

20 of the supplement ingredients on this page reach Dextromethorphan HBr through this category.

Oral Drugs 17 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

17 of the supplement ingredients on this page reach Dextromethorphan HBr through this category.

Dextromethorphan (Robitussin Dm, Others) 9 ingredients

A pharmacology grouping from our source database: medications in this group share a property that certain supplements are known to interact with, so an interaction documented for the group applies to every drug in it.

9 of the supplement ingredients on this page reach Dextromethorphan HBr through this category.

Serotonergic Drugs 1 ingredient

Medications that raise serotonin activity. Combining them with serotonin-active supplements can, in rare cases, push serotonin too high.

1 of the supplement ingredient on this page reaches Dextromethorphan HBr through this category.

Check a real product

Take a Supplement Product? Check the Whole Bottle Against Dextromethorphan HBr

Most supplements are combination products — and the interaction may come from an ingredient you didn’t buy it for. Search any product below (or scan its label) and we’ll check every ingredient on it against Dextromethorphan HBr.

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Pharmacist Counseling Corner

Dextromethorphan HBr & Supplements: Common Questions

What supplements interact with Dextromethorphan HBr?
Our database currently documents 171 ingredients with a known Dextromethorphan HBr interaction (4 major, 125 moderate, 42 minor). The practical move: scan the major group first, then look up the exact supplements you take rather than reading all 171. The highest-ranked right now: Grapefruit, Activated Charcoal, Lithium.
Which Dextromethorphan HBr supplement interactions are the most serious?
Focus on the major group: Grapefruit, Activated Charcoal, Lithium and St. John's Wort. A major rating means the combination can be clinically significant, not that harm is guaranteed — but it's exactly the kind of thing to run past your pharmacist before your next dose, not after. Jump to the ranked list.
Can I take vitamins or supplements while on Dextromethorphan HBr?
Plenty of supplements coexist fine with Dextromethorphan HBr; a shorter list does not. Rather than memorizing it, check the specific ingredients on your labels — the ranked list above covers every one we've checked, and multi-ingredient products can be checked label-by-label with our scanner. Try the label scanner or the interaction checker.
Do brands like Vicks Formula 44 Cough Relief have the same supplement interactions as Dextromethorphan HBr?
Yes — Vicks Formula 44 Cough Relief all contain Dextromethorphan HBr, so everything on this page applies to them equally. Interactions belong to the active drug, never to the brand on the box; the same is true of generics.
Where do these interaction ratings come from?
Every rating comes from the Natural Medicines database — the same evidence-graded reference pharmacists and hospitals use — and each interaction carries three separate grades: severity (how bad it can be), likelihood (how well it's documented in studies and case reports), and an evidence level. Our pharmacists review the content; we never let an AI decide an interaction. See how to read the ratings and our editorial policy.
What about Dextromethorphan HBr and my other medications?
This page covers Dextromethorphan HBr against supplements and herbal ingredients. Checking Dextromethorphan HBr against your other prescription or OTC medications is a different tool — our drug interaction checker covers that side. Head to the drug–drug interaction checker.

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

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Sourcing

Where This Data Comes From — and Why You Can Trust It

🧪 Licensed clinical database

Every interaction verdict on this page comes from Natural Medicines Pro (TRC Healthcare / Therapeutic Research) — the same evidence-graded reference used by pharmacists and hospitals. We license this data directly; we do not scrape it, and no AI invents an interaction.

🧑‍⚕️ Pharmacist review

This page is curated and coded by , Clinical Pharmacist, with additional analysis by the HelloPharmacist Pharmacist Team. Editorial commentary is ours; the licensed interaction records are shown as sourced.

🔄 Kept current

Our interaction database refreshes on a weekly cycle, and this page re-checks the live database every time it’s rebuilt — what you see reflects the database as of September 22, 2026.

🔍 Full transparency

How every dataset on this site is sourced, licensed, and updated is documented publicly: our data sources · editorial policy · how we use AI.

Educational information, not medical advice. An interaction being on file does not mean it will happen to you — and absence of one is not proof of safety. Never start or stop a medication or supplement without talking to your pharmacist or doctor.