Drug & supplement interaction

Psilocybin + Acetaminophen, Dextromethorphan, Pseudoephedrine

Acetaminophen, Dextromethorphan, Pseudoephedrine brand names: Alka-Seltzer PLUS Flu Liquid Gels, Tylenol Flu Daytime Ex Strength, Non Aspirin Cold Caps, Tylenol Cold, Tylenol Flu Ex Strength.

Moderate Interaction
The bottom line Moderate

Acetaminophen, Dextromethorphan, Pseudoephedrine falls into 2 drug categories that Psilocybin can interact with; the most serious is rated moderate. Theoretically, combining psilocybin with serotonergic drugs might cause additive serotonergic effects.

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

Psilocybin and Acetaminophen, Dextromethorphan, Pseudoephedrine

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

Why Are There 2 Interactions?

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

Moderate

SEROTONERGIC DRUGS

1 of 2

Why this applies to Acetaminophen, Dextromethorphan, Pseudoephedrine

Acetaminophen, Dextromethorphan, Pseudoephedrine falls under SEROTONERGIC DRUGS — the group Psilocybin interacts with.

Theoretically, combining psilocybin with serotonergic drugs might cause additive serotonergic effects.
Psilocybin has serotonin 2A (5-HT2A) receptor agonist activity. Theoretically, combining serotonergic drugs with psilocybin might increase the risk of serotonergic side effects, including serotonin syndrome. However, this interaction has not been reported in humans.
Severity Moderate 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

This is a combination cold and flu product, and the piece that matters here is the dextromethorphan (the cough suppressant). Dextromethorphan nudges serotonin activity in the brain, and psilocybin works on serotonin receptors too. On paper, stacking them could add up and raise the chance of too much serotonin, which can show up as agitation, a racing heart, sweating, shivering, tremor, or confusion. Pseudoephedrine, a stimulant decongestant, could add to that jittery, fast-heartbeat feeling.

I want to be honest: this is a theoretical concern drawn from how these act, not something actually reported in people. Still, psilocybin is unpredictable and not approved for use. Please run any combination past your pharmacist or doctor before mixing them.

References
  1. Rosenbaum D, Weissman C, Anderson T, et al. Microdosing psychedelics: Demographics, practices, and psychiatric comorbidities. J Psychopharmacol 2020;34(6):612-622. PubMed
  2. Higgins GA, Carroll NK, Brown M, et al. Low Doses of Psilocybin and Ketamine Enhance Motivation and Attention in Poor Performing Rats: Evidence for an Antidepressant Property. Front Pharmacol 2021;12:640241. PubMed
  3. Hesselgrave N, Troppoli TA, Wulff AB, Cole AB, Thompson SM. Harnessing psilocybin: antidepressant-like behavioral and synaptic actions of psilocybin are independent of 5-HT2R activation in mice. Proc Natl Acad Sci U S A 2021;118(17):e2022489118. PubMed
  4. Winter JC, Rice KC, Amorosi DJ, Rabin RA. Psilocybin-induced stimulus control in the rat. Pharmacol Biochem Behav 2007;87(4):472-80. PubMed
  5. Kometer M, Schmidt A, Bachmann R, Studerus E, Seifritz E, Vollenweider FX. Psilocybin biases facial recognition, goal-directed behavior, and mood state toward positive relative to negative emotions through different serotonergic subreceptors. Biol Psychia PubMed
Moderate

STIMULANT DRUGS

2 of 2

Acetaminophen, Dextromethorphan, Pseudoephedrine also falls under STIMULANT DRUGS.

Theoretically, concomitant use of psilocybin with stimulant drugs might increase stimulant adverse effects.
Due to the central nervous system (CNS) stimulant effects of psilocybin, concomitant use with stimulant drugs may increase the risk of adverse effects.
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 part that matters in this combo product: the pseudoephedrine is a stimulant decongestant, and on its own it can speed up your heart, raise your blood pressure, and leave you feeling jittery or wired. The concern with psilocybin is that it also revs up the nervous system, so stacking the two could pile on those stimulant-type effects. The dextromethorphan adds another wrinkle, since it also touches serotonin pathways like psilocybin does.

To be honest, this is a theoretical caution based on how these compounds work, not on solid studies, so I don't want to overstate it. Still, faster heartbeat, anxiety, and spiking blood pressure are nothing to gamble with. Please run this by your pharmacist or doctor before mixing them.

References
  1. Griffiths RR, Johnson MW, Carducci MA, et al. Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial. J Psychopharmacol 2016;30(12):1181-1197. PubMed
  2. Bogenschutz MP, Forcehimes AA, Pommy JA, Wilcox CE, Barbosa PC, Strassman RJ. Psilocybin-assisted treatment for alcohol dependence: a proof-of-concept study. J Psychopharmacol 2015;29(3):289-99. PubMed
  3. Grob CS, Danforth AL, Chopra GS, et al. Pilot study of psilocybin treatment for anxiety in patients with advanced-stage cancer. Arch Gen Psychiatry 2011;68(1):71-8. PubMed
  4. Brown RT, Nicholas CR, Cozzi NV, et al. Pharmacokinetics of Escalating Doses of Oral Psilocybin in Healthy Adults. Clin Pharmacokinet 2017;56(12):1543-1554. PubMed
  5. Carbonaro TM, Bradstreet MP, Barrett FS, et al. Survey study of challenging experiences after ingesting psilocybin mushrooms: Acute and enduring positive and negative consequences. J Psychopharmacol 2016;30(12):1268-1278. PubMed
  6. Hasler F, Grimberg U, Benz MA, Huber T, Vollenweider FX. Acute psychological and physiological effects of psilocybin in healthy humans: a double-blind, placebo-controlled dose-effect study. Psychopharmacology (Berl) 2004;172(2):145-56. PubMed
  7. Bienemann B, Ruschel NS, Campos ML, Negreiros MA, Mograbi DC. Self-reported negative outcomes of psilocybin users: A quantitative textual analysis. PLoS One 2020;15(2):e0229067. PubMed
  8. Carbonaro TM, Johnson MW, Griffiths RR. Subjective features of the psilocybin experience that may account for its self-administration by humans: a double-blind comparison of psilocybin and dextromethorphan. Psychopharmacology (Berl) 2020;237(8):2293-2304. PubMed
  9. Anderson BT, Danforth A, Daroff PR, et al. Psilocybin-assisted group therapy for demoralized older long-term AIDS survivor men: An open-label safety and feasibility pilot study. EClinicalMedicine 2020;27:100538. PubMed
  10. Carbonaro TM, Johnson MW, Hurwitz E, Griffiths RR. Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: similarities and differences in subjective experiences. Psychopharmacology (Berl) 2018;235(2):521-534. PubMed
  11. Bravermanová A, Viktorinová M, Tyl š F, et al. Psilocybin disrupts sensory and higher order cognitive processing but not pre-attentive cognitive processing-study on P300 and mismatch negativity in healthy volunteers. Psychopharmacology (Berl) 201 PubMed
  12. Wackermann J, Wittmann M, Hasler F, Vollenweider FX. Effects of varied doses of psilocybin on time interval reproduction in human subjects. Neurosci Lett 2008;435(1):51-5. PubMed
  13. Fadiman J, Korb S. Might Microdosing Psychedelics Be Safe and Beneficial? An Initial Exploration. J Psychoactive Drugs 2019;51(2):118-122. 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

Psilocybin Also Interacts With Other Medications

Psilocybin has 292 moderate known drug interactions in our database — the Acetaminophen, Dextromethorphan, Pseudoephedrine one above is among them. If you take anything else, check it against the full list below.

Taking anything else?

Check Another of Your Medications Against Psilocybin

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

Everything else you take

See Every Supplement That Interacts With Acetaminophen, Dextromethorphan, Pseudoephedrine

This page covers Psilocybin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Dextromethorphan, Pseudoephedrine page lists 262 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: 12 major · 207 moderate · 43 minor.

From our pharmacist’s overview on the Acetaminophen, Dextromethorphan, Pseudoephedrine page

“Ephedra is the ingredient to notice first here. Pseudoephedrine, the decongestant in Tylenol Flu, Alka-Seltzer PLUS Flu, and other acetaminophen, dextromethorphan, and pseudoephedrine combinations, is itself a stimulant, and 44 entries push the same direction, raising the odds of high blood pressure and a racing heart.”

Reviewed by 2 · Jul 18, 2026

Open the Acetaminophen, Dextromethorphan, Pseudoephedrine interaction page

How much people look this up

Where Psilocybin and Acetaminophen, Dextromethorphan, Pseudoephedrine 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 Psilocybin
Top half

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

29 days ago today
Medication Acetaminophen, Dextromethorphan, Pseudoephedrine
Top 25%

#364 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 Psilocybin

What is Psilocybin?

  • Depression
  • Anxiety (including in serious illness)
  • Substance use disorders
  • Post-traumatic stress
  • Spiritual or psychological exploration

Psilocybin is a powerful psychedelic compound found in certain mushrooms and is being studied for hard-to-treat depression, anxiety, and addiction, but it is still investigational and not an approved supplement. It is illegal in most places, can cause intense and unpredictable mental effects, and should never be used outside of a supervised clinical setting.

Read the full Psilocybin monograph & all interactions
Keep checking

Other Drugs & Psilocybin

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

0Major
292Moderate
0Minor
2,537No known interaction
Moderate

292 interactions

Showing 60 of 292 moderate interactions — see all 292 on the Psilocybin page.

No interaction 2,537 drugs checked — show the list
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

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Pharmacist Counseling Corner

Taking Psilocybin and Acetaminophen, Dextromethorphan, Pseudoephedrine Together: Common Questions

Can you take Psilocybin with Acetaminophen, Dextromethorphan, Pseudoephedrine?
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.
Why are there 2 interactions listed for Psilocybin and Acetaminophen, Dextromethorphan, Pseudoephedrine?
Acetaminophen, Dextromethorphan, Pseudoephedrine belongs to more than one drug category, and Psilocybin 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 Psilocybin and Acetaminophen, Dextromethorphan, Pseudoephedrine 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

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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.