Drug & supplement interaction

Hops + Acetaminophen, Chlorpheniramine, Phenylephrine

Acetaminophen, Chlorpheniramine, Phenylephrine brand names: Protid, Histex SR, Alka-Seltzer PLUS.

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

Acetaminophen, Chlorpheniramine, Phenylephrine falls into 2 drug categories that Hops can interact with; the most serious is rated minor. Hops extract does not seem to affect the metabolism of CYP1A2 substrates.

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

Hops and Acetaminophen, Chlorpheniramine, Phenylephrine

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

Why Are There 2 Interactions?

Hops interacts with whole categories of medication. Acetaminophen, Chlorpheniramine, Phenylephrine falls into 2 of those categories, so it can interact with Hops in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Minor).

Minor

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

1 of 2

Why this applies to Acetaminophen, Chlorpheniramine, Phenylephrine

Acetaminophen, Chlorpheniramine, Phenylephrine falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Hops interacts with.

Hops extract does not seem to affect the metabolism of CYP1A2 substrates.
In vitro research suggests that flavonoid constituents of hops inhibit CYP1A2 enzyme activity. However, a pharmacokinetic study in healthy postmenopausal patients shows that taking a standardized extract of spent hops containing prenylated phenols, as 59.5 mg twice daily for 2 weeks, does not affect levels of caffeine, a CYP1A2 probe substrate.
Severity Minor Likelihood Unlikely Evidence D

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans..

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

Good news here: this combo product (acetaminophen for pain and fever, chlorpheniramine as an antihistamine, and phenylephrine as a decongestant) doesn't appear to have a real interaction with hops. The concern came only from lab dish studies, where hops flavonoids slowed an enzyme called CYP1A2. But when researchers actually gave people standardized hops and checked it against caffeine (a marker for that same enzyme), nothing changed. So the worry didn't pan out in real life.

The one practical thing I'd mention: both hops and chlorpheniramine can make you sleepy. Taken together, you may feel more drowsy than usual. If you notice that, or have questions, just check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Henderson MC, Miranda CL, Stevens JF, et al. In vitro inhibition of human P450 enzymes by prenylated flavonoids from hops, Humulus lupulus. Xenobiotica 2000;30:235-51.. PubMed
  2. van Breemen RB, Chen L, Tonsing-Carter A, et al. Pharmacokinetic Interactions of a Hop Dietary Supplement with Drug Metabolism in Perimenopausal and Postmenopausal Women. J Agric Food Chem. 2020;68(18):5212-5220. PubMed
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

Acetaminophen, Chlorpheniramine, Phenylephrine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, hops extract might alter metabolism of CYP3A4 substrates; however, this effect may not be clinically significant.
Animal research suggests that specific constituents of hops, called lupulones, can induce hepatic CYP3A4 enzyme activity. However, a pharmacokinetic study in healthy postmenopausal patients with normal metabolism shows that taking a standardized extract of spent hops containing prenylated phenols, as 59.5 mg twice daily for 2 weeks, decreases the concentration of alprazolam, a CYP3A4 probe substrate, by 7.6%. This reduction is unlikely to be clinically relevant.
Severity Minor 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

Good news here: the concern with hops and this cold and allergy combo (acetaminophen, chlorpheniramine, and phenylephrine) is really minor and mostly theoretical. In lab and animal studies, certain hops compounds may slightly speed up a liver enzyme called CYP3A4, which helps process some medicines. In real people, though, a human study found only about an 8% drop in a test drug's level, which is too small to matter.

So practically speaking, hops are very unlikely to weaken these ingredients or change how you feel. The bigger thing I'd mention is overlap in drowsiness. Hops can make you sleepy, and so can chlorpheniramine (the antihistamine), so together they may leave you feeling more tired. If you take these often, just check with your pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Mannering, G. J., Shoeman, J. A., and Deloria, L. B. Identification of the antibiotic hops component, colupulone, as an inducer of hepatic cytochrome P-4503A in the mouse. Drug Metab Dispos 1992;20(2):142-147. DOI
  2. van Breemen RB, Chen L, Tonsing-Carter A, et al. Pharmacokinetic Interactions of a Hop Dietary Supplement with Drug Metabolism in Perimenopausal and Postmenopausal Women. J Agric Food Chem. 2020;68(18):5212-5220. 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

Hops Also Interacts With Other Medications

Hops has 289 moderate, 573 minor known drug interactions in our database — the Acetaminophen, Chlorpheniramine, Phenylephrine one above is among them. If you take anything else, check it against the full list below.

Moderate 289 Minor 573 No known interaction 1,968 (incl. Acetaminophen, Chlorpheniramine, Phenylephrine)
Taking anything else?

Check Another of Your Medications Against Hops

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

Everything else you take

See Every Supplement That Interacts With Acetaminophen, Chlorpheniramine, Phenylephrine

This page covers Hops only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Chlorpheniramine, Phenylephrine page lists 292 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Ephedra (major) and Grapefruit (major).

By severity: 14 major · 232 moderate · 46 minor.

From our pharmacist’s overview on the Acetaminophen, Chlorpheniramine, Phenylephrine page

“Picture the week you are sick enough to reach for Alka-Seltzer PLUS or another acetaminophen, chlorpheniramine, and phenylephrine combination, while still taking whatever supplements you always take. That is where trouble hides, and with 14 of its 292 supplement interactions rated major, this medicine warrants real vigilance.”

Reviewed by 2 · Jul 18, 2026

Open the Acetaminophen, Chlorpheniramine, Phenylephrine interaction page

One more smart check

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

We hold 1,325 real supplement products containing Hops, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Hops. Your product may carry other ingredients that interact with Acetaminophen, Chlorpheniramine, Phenylephrine too, on top of Hops — 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 Hops and Acetaminophen, Chlorpheniramine, Phenylephrine 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 Hops
Top 25%

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

29 days ago today
Medication Acetaminophen, Chlorpheniramine, Phenylephrine
Top 25%

#526 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 Hops

What is Hops?

Hops
  • Sleep problems and insomnia
  • Anxiety and restlessness
  • Menopausal symptoms
  • Mild digestive complaints
  • Flavoring in beer and food

Hops are most often used for sleep and mild anxiety, frequently combined with valerian, but the human evidence is limited and not very strong. They are generally well tolerated when used short-term, though they may cause drowsiness, and should be avoided during pregnancy and breastfeeding because their safety is unknown.

Read the full Hops monograph & all interactions
Keep checking

Other Drugs & Hops

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

0Major
289Moderate
573Minor
1,967No known interaction
289 Moderate 573 Minor 1,967 No interaction
Moderate

289 interactions

Showing 60 of 289 moderate interactions — see all 289 on the Hops page.

Minor

573 interactions

Showing 60 of 573 minor interactions — see all 573 on the Hops page.

No interaction 1,967 drugs checked — show the list

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

Showing the 60 most looked-up of 1,967 medications checked with no known interaction — see the full Hops list.

See the full Hops interactions page
See every supplement checked against Acetaminophen, Chlorpheniramine, Phenylephrine, 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
Hops monograph › Uses, safety, and every drug interaction in one place Acetaminophen, Chlorpheniramine, Phenylephrine supplement interactions › Every supplement checked against Acetaminophen, Chlorpheniramine, Phenylephrine, 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 Hops and Acetaminophen, Chlorpheniramine, Phenylephrine Together: Common Questions

Can you take Hops with Acetaminophen, Chlorpheniramine, Phenylephrine?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 2 interactions listed for Hops and Acetaminophen, Chlorpheniramine, Phenylephrine?
Acetaminophen, Chlorpheniramine, Phenylephrine belongs to more than one drug category, and Hops 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 Hops and Acetaminophen, Chlorpheniramine, Phenylephrine interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Acetaminophen, Chlorpheniramine, Phenylephrine and Hops?

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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.