Feverfew + Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine brand name: Theracaps.
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls into 3 drug categories that Feverfew can interact with; the most serious is rated moderate. Theoretically, feverfew might increase levels of drugs metabolized by CYP2D6.
Read the full interaction reportFeverfew and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
These two interact in 3 distinct ways. Each one is explained separately below.
Why Are There 3 Interactions?
Feverfew interacts with whole categories of medication. Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls into 3 of those categories, so it can interact with Feverfew in 3 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).
CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES
1 of 3Why this applies to Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES — the group Feverfew interacts with.
Laboratory research shows that feverfew might inhibit CYP2D6. So far, this interaction has not been reported in humans.
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.
This combination product (often sold as Theracaps) is a cold-and-cough mix, and the piece that matters here is the dextromethorphan, the cough suppressant. Your body clears dextromethorphan using an enzyme called CYP2D6. Feverfew, in laboratory studies only, appears to slow that same enzyme down. If that happened in real life, dextromethorphan could build up a bit and lead to things like drowsiness, dizziness, or feeling foggy. The acetaminophen, phenylpropanolamine, and pyrilamine pieces are not really driven by this enzyme.
Here's the reassuring part: this is theoretical, based on test-tube work, and has never actually been reported in people. For most short-term use it's unlikely to cause trouble, but it's always smart to run it by your pharmacist or doctor first.
- Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 PubMed
CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES
2 of 3Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine also falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES.
Laboratory research shows that feverfew might inhibit CYP1A2. So far, this interaction has not been reported in humans.
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.
This combo product (Theracaps) bundles a fever and pain reducer, a cough suppressant, a decongestant, and an antihistamine. The concern here is theoretical: lab studies suggest feverfew might slow down a liver enzyme called CYP1A2. If that enzyme runs slower, certain medicines it handles could build up a bit. This has never actually been seen in real people, so it lands at the bottom of the evidence ladder.
If anything did happen, you might notice slightly more of the usual effects, like drowsiness from the antihistamine, dizziness, or a jittery feeling from the decongestant. For most healthy adults using these together short-term, this is very unlikely to cause trouble. Still, it's worth a quick word with your pharmacist or doctor, especially if you take feverfew daily for migraines.
- Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 PubMed
CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES
3 of 3Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.
Laboratory research shows that feverfew might inhibit CYP3A4. So far, this interaction has not been reported in humans.
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.
Theracaps is a combo cold and cough product, and one of its ingredients, dextromethorphan (the cough suppressant), is partly broken down by a liver enzyme called CYP3A4. Feverfew, in lab dish studies only, has shown it might slow that enzyme down. If that happened in real life, dextromethorphan could build up a bit and you might notice more drowsiness, dizziness, or feeling foggy.
Here's the honest part: this is purely theoretical, based on test-tube research, and it has never actually been reported in people. So I wouldn't lose sleep over it. Still, since this product also contains a decongestant and an antihistamine, it's worth a quick chat with your pharmacist or doctor before combining it with feverfew, just to be safe.
- Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1 PubMed
- Sil'vestrov VP, Kinitin AV, and Chesnokova, IV. [Immunological and metabolic disorders and the means for their correction in patients with chronic bronchitis]. Ter.Arkh. 1991;63:7-11.
What These Ratings Mean
Every interaction above is graded three ways — here’s the key to each label.
Clinically significant. Avoid the combination, or use only under close professional supervision.
Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.
Generally not serious. Be aware of it and mention it to your pharmacist.
- 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.
- 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.
Feverfew Also Interacts With Other Medications
Feverfew has 928 moderate known drug interactions in our database — the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine one above is among them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Feverfew
We haven’t checked that one against Feverfew yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Feverfew. Pick one to open its full report.
See Every Supplement That Interacts With Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
This page covers Feverfew only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine page lists 282 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 · 223 moderate · 45 minor.
From our pharmacist’s overview on the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine page
“Of everything on this page, ephedra worries me most for anyone using Theracaps (acetaminophen, dextromethorphan, phenylpropanolamine, and pyrilamine), because the decongestant in this cold formula is itself a stimulant. Adding ephedra or any of the 44 stimulant entries can push blood pressure and heart rate to unsafe levels.”
Reviewed by 2 · Jul 18, 2026
Open the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine interaction page
Taking Feverfew as Part of a Dietary Supplement Product? Check It for Interactions
We hold 520 real supplement products containing Feverfew, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Feverfew. Your product may carry other ingredients that interact with Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine too, on top of Feverfew — and those would not show on this page. Find your product and we’ll check every ingredient on its label:
Where Feverfew and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine 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.
#339 of 1,452 supplements looked up here in the last 7 days
#1,288 of 2,830 medications looked up here in the last 7 days
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.
About Feverfew
What is Feverfew?
- Migraine prevention
- Headache
- Fever (traditional)
- Arthritis and joint pain
- Menstrual discomfort
Feverfew is a daisy-family herb best known for migraine prevention, where some studies suggest it may modestly lower how often migraines occur, though the evidence is mixed. It is generally well tolerated for short-term use in most adults but should be avoided during pregnancy and breastfeeding and by people allergic to ragweed and related plants. Talk to your pharmacist or doctor before starting it.
Other Drugs & Feverfew
Browse every other medication we’ve checked against Feverfew — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
928 interactions
- Diclofenac Sodium ›
- Diltiazem ›
- Theophylline ›
- Nifedipine ›
- Ibuprofen ›
- Aspirin ›
- Hydrocortisone ›
- Naproxen ›
- Erythromycin ›
- Estradiol ›
- Minocycline ›
- Propranolol ›
- Lidocaine ›
- Norethindrone ›
- Testosterone ›
- Verapamil ›
- Levonorgestrel ›
- Prednisone ›
- Quinidine ›
- Cyclosporine ›
- Dexamethasone ›
- Glyburide ›
- Triazolam ›
- Zopiclone ›
- Colchicine ›
- Fentanyl ›
- Flurbiprofen ›
- Isotretinoin ›
- Oxybutynin ›
- Oxycodone ›
- Phenytoin ›
- Prednisolone ›
- Tacrolimus ›
- Temazepam ›
- Budesonide ›
- Carbamazepine ›
- Clindamycin ›
- Dextromethorphan ›
- Diclofenac Potassium ›
- Dipyridamole ›
- Doxorubicin ›
- Fluticasone ›
- Formoterol ›
- Indomethacin ›
- Miconazole ›
- Morphine Sulfate ›
- Trimipramine ›
- Acetaminophen ›
- Amphetamine ›
- Buprenorphine ›
- Conjugated Estrogens ›
- Diazepam ›
- Everolimus ›
- Ivabradine ›
- Ketoprofen ›
- Lofepramine ›
- Medroxyprogesterone ›
- Medroxyprogesterone Acetate ›
- Meloxicam ›
- Nortriptyline ›
Showing 60 of 928 moderate interactions — see all 928 on the Feverfew page.
No interaction 1,901 drugs checked — show the list
We also checked Feverfew against these medications and found no known interaction in our sources. Open any page to confirm.
- Levothyroxine ›
- Methylphenidate ›
- Ivermectin ›
- Rosuvastatin ›
- Escitalopram ›
- Valacyclovir ›
- Docusate ›
- Hydroxyurea ›
- Sumatriptan ›
- Semaglutide ›
- Tirzepatide ›
- Acyclovir ›
- Bupropion ›
- Metformin ›
- Amoxicillin ›
- Lisinopril ›
- Doxycycline ›
- Lamotrigine ›
- Methotrexate ›
- Gabapentin ›
- Pregabalin ›
- Azithromycin ›
- Methylene Blue ›
- Ciprofloxacin ›
- Levothyroxine, Liothyronine ›
- Cyclopentolate ›
- Candesartan Cilexetil ›
- Mannitol ›
- Cephalexin ›
- Roxithromycin ›
- Pegunigalsidase Alfa-iwxj ›
- Acetaminophen, Dextromethorphan, Doxylamine ›
- Daptomycin ›
- Hexobarbitone ›
- Dexmethylphenidate ›
- Levothyroxine Sodium ›
- Levetiracetam ›
- Mitomycin ›
- Minoxidil ›
- Cefaclor ›
- Factor 7a ›
- Carbidopa, Levodopa ›
- Thyroid Hormone ›
- Ezetimibe ›
- Levodopa ›
- Vancomycin ›
- Phenylephrine ›
- Spironolactone ›
- Dirithromycin ›
- Procainamide ›
- Lenvatinib ›
- Hethylphenidate Hcl ›
- Phentermine, Topiramate ›
- Azelaic Acid ›
- Bentoquatam ›
- Amoxicillin, Clavulanate Potassium ›
- Hydroxychloroquine ›
- Digoxin ›
- Dextrothyroxine ›
- Triptorelin ›
Showing the 60 most looked-up of 1,901 medications checked with no known interaction — see the full Feverfew list.
Sources & How We Checked
Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for vitamins, herbs and supplements — the basis for our interaction data.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for the medication overviews.
- NIH Dietary Supplement Label Database (DSLD) — Official supplement product labels.
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
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine Is Linked to Lower Levels of One Nutrient
Natural Medicines records Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine as a medicine that can lower these. This is not an interaction with Feverfew — it is a separate effect of the medicine, and it is a reason some people are advised to supplement rather than to avoid one:
Depletion records come from the licensed Natural Medicines database. Do not start a supplement on the strength of this page — ask your pharmacist or doctor whether it applies to you.
Taking Feverfew and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine Together: Common Questions
Can you take Feverfew with Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine?
Why are there 3 interactions listed for Feverfew and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine?
How serious is the Feverfew and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine interaction?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Still Have a Question About Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine and Feverfew?
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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.