Drug & supplement interaction

Phenethylamine (pea) + Gefitinib

Gefitinib brand name: Iressa.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated July 2026 · Pair last verified Sep 13, 2026

The bottom line No known interaction

We found no known interaction between Phenethylamine (pea) and Gefitinib in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Phenethylamine (pea) and Gefitinib

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Gefitinib and Phenethylamine (pea) in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Phenethylamine (pea) safety at a glance

Phenethylamine (pe... overall Use caution May affect heart rate and blood pressure, and human safety data for supplements is limited.

Pregnancy Avoid Not enough safety information; best avoided during pregnancy.

Breastfeeding Avoid Not enough safety information; best avoided while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Gefitinib and Phenethylamine (pea)? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Gefitinib

Interactions in our licensed database are recorded against drug classes, not just single drug names. Gefitinib is filed under 3 classifications — hepatotoxic drugs, cytochrome p450 3a4 (cyp3a4) substrates, oral drugs. Phenethylamine (pea) has documented interactions with 2 drug classes — the most serious being monoamine oxidase inhibitors (maois) (moderate) and serotonergic drugs (moderate) — and none of Gefitinib’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Phenethylamine (pea) Does Interact With Other Medications

Phenethylamine (pea) has 187 moderate known drug interactions in our database — Gefitinib isn’t one of them. If you take anything else, check it against the full list below.

Moderate 187 No known interaction 2,643 (incl. Gefitinib)

Taking anything else?

Check Another of Your Medications Against Phenethylamine (pea)

Covers the 2,830 medications we’ve checked against Phenethylamine (pea). Pick one to open its full report.

What to actually watch for

What Phenethylamine (pea) Itself Has Been Linked To

This is not an interaction — nothing below involves Gefitinib. It is the side-effect record for Phenethylamine (pea) on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Phenethylamine (pea), this list is the first place to look.

Weight loss Additional detail
“A case of anxiety and agitation has been reported for an individual who consumed a weight loss product containing phenethylamine 200-300 mg, caffeine 500-750 mg, bitter orange 400-600 mg, willow bark 150-225 mg, cayenne pepper 80-120 mg, 1,3-dimethyloamyloamine 70-105 mg, gooseberry extract 40-60 mg, bergamot orange 40-60 mg, and black pepper 10-15 mg, daily for 2 months.”

Phenethylamine (pea) · Natural Medicines adverse-effect record, reported in anxiety.
1 source cited

24343. Lukasik-Glebocka M, Sommerfeld K, Tezyk A, et al. [Acute poisoning with weight-loss dietary supplement falsely suggesting the use of amphetamine]. Przegl Lek. 2013;70(10):880-3.
“A case of tachycardia has been reported for an individual who consumed a weight loss product containing phenethylamine 200-300 mg, as well as caffeine 500-750 mg, bitter orange 400-600 mg, willow bark 150-225 mg, cayenne pepper 80-120 mg, 1,3-dimethyloamyloamine 70-105 mg, gooseberry extract 40-60 mg, bergamot orange 40-60 mg, and black pepper 10-15 mg, daily for 2 months.”

Phenethylamine (pea) · Natural Medicines adverse-effect record, reported in myasthenia gravis.
1 source cited

24343. Lukasik-Glebocka M, Sommerfeld K, Tezyk A, et al. [Acute poisoning with weight-loss dietary supplement falsely suggesting the use of amphetamine]. Przegl Lek. 2013;70(10):880-3.
A fast or pounding heartbeat Additional detail

Recorded for Phenethylamine (pea) in the same Natural Medicines adverse-effect record shown under Weight loss above.
Anxiety or restlessness Additional detail

Recorded for Phenethylamine (pea) in the same Natural Medicines adverse-effect record shown under Weight loss above.

Everything above comes from the Natural Medicines adverse-effect record for Phenethylamine (pea) — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Gefitinib’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Gefitinib column appears here.

Everything else you take

See Every Supplement That Interacts With Gefitinib

This page covers Phenethylamine (pea) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Gefitinib page lists 168 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Grapefruit (major), Siberian Cocklebur (major) and St. John's Wort (major).

By severity: 6 major · 124 moderate · 38 minor.

Open the Gefitinib interaction page

One more smart check

Taking Phenethylamine (pea) as Part of a Dietary Supplement Product? Check It for Interactions

We hold 208 real supplement products containing Phenethylamine (pea), each one broken down to its full ingredient list — and combination products often carry several ingredients besides Phenethylamine (pea). Even though Phenethylamine (pea) itself has no known interaction with Gefitinib, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Phenethylamine (pea) and Gefitinib 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 Phenethylamine (pea)

Top half

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

29 days ago today

Medication Gefitinib

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.

Where does our data come from?

Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Phenethylamine (pea) reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Phenethylamine (pea) and Gefitinib records this page draws on were last updated July 10, 2026.
What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.

Data structure & sourcing designed and verified by Dr. Brian Staiger, PharmD, BCPS.

Supplement

About Phenethylamine (pea)

What is Phenethylamine (pea)?

Mood support
Focus and concentration
Energy and pre-workout boost
Feeling of well-being
Athletic performance

Phenethylamine (PEA) is a natural compound made in the body and found in foods like chocolate; supplements are marketed for mood, focus, and energy. Reliable human research on the supplement is very limited, and it may raise blood pressure or heart rate, so people with heart or blood pressure problems should be cautious and check with a pharmacist or doctor first.

Not a plant part; a naturally occurring monoamine compound (made in the body and found in some foods) · Capsules, tablets, powders (often combined with other ingredients in pre-workout or 'mood' and 'focus' supplements)

An interaction check asks whether these two react with each other — it does not ask whether Phenethylamine (pea) is a good idea for someone in your situation. Here is what our Phenethylamine (pea) record says about it on its own.

Phenethylamine (pea): dosing

There is no well-established or standardized dose for PEA supplements, and reliable studies on safe and effective amounts are lacking. Products vary widely in how much they contain and what else they are combined with.If you choose to try it, follow the directions on the product label and do not exceed the recommended amount.

From our Phenethylamine (pea) monograph — the full record covers uses, side effects and every documented interaction.

Read the full Phenethylamine (pea) monograph & all interactions

Medication

About Gefitinib

What Is Gefitinib Used For?

Brand name: Iressa

Gefitinib tablets — sold under the brand name Iressa — are used as a first-line treatment for metastatic non-small cell lung cancer (NSCLC). This treatment is only for patients whose tumors carry specific changes (mutations) in the EGFR gene: either an exon 19 deletion or an exon 21 (L858R) substitution mutation, confirmed by an FDA-approved test.

This medicine is not established as safe or effective for NSCLC patients with other types of EGFR mutations. Your doctor will use a genetic test on your tumor or blood to confirm whether gefitinib is right for you.

Most-Reported Side Effects for Gefitinib

From FAERS, the FDA’s public side-effect reporting system (8,974 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Malignant neoplasm progression 1,821 reports

Drug resistance 1,251 reports

Diarrhea 904 reports

Rash 643 reports

Disease progression 461 reports

See full Gefitinib drug information

Keep checking

Other Drugs & Phenethylamine (pea)

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

0Major

187Moderate

0Minor

2,642No known interaction

187 Moderate 2,642 No interaction

Moderate

187 interactions

Showing 60 of 187 moderate interactions — see all 187 on the Phenethylamine (pea) page.

No interaction 2,642 drugs checked — show the list

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

Showing the 60 most looked-up of 2,642 medications checked with no known interaction — see the full Phenethylamine (pea) list.

See the full Phenethylamine (pea) interactions page

See every supplement checked against Gefitinib, ranked by severity

Evidence & sources

Phenethylamine (pea) References

The 9 references that drive our Phenethylamine (pea) monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3. PubMed
Sabelli H, Fink P, Fawcett J, et al. Sustained antidepressant effect of PEA replacement. J Neuropsychiatry Clin Neurosci. 1996;8(2):168-71.
Xie Z, Miller G. Beta-phenylehtylamine alters monoamine transporter function via trace amine-associated receptor 1: implication for modulatory roles of trace amines in brain. J Pharmacol Exp Ther. 2008;325(2):617-28.
Lukasik-Glebocka M, Sommerfeld K, Tezyk A, et al. [Acute poisoning with weight-loss dietary supplement falsely suggesting the use of amphetamine]. Przegl Lek. 2013;70(10):880-3.
Nakamura M, Ishii A, Nakahara D. Characterization of beta-phenyltheylamine-induced monoamine release in rat nucleus accumbens: a microdialysis study. Eur J Pharmacol. 1998;349(2-3):163-9.
Bailey B, Philips S, Boulton A. In vivo release of endogenous dopamine, 5-hydroxytryptamine and some of their metabolites from rat caudate nucleus by phenylethylamine. Neurochem Res. 1987;12(2):173-8. PubMed
Mantegazza P, Riva M. Amphetamine-like activity of beta-phenethylamine after a monoamine oxidase inhibitor in vivo. Journal of Pharmacy and Pharmacology. 1963;151(1):472-8.
Grimsby J, Toth M, Chen K, et al. Increased stress response and beta-phenylethylamine in MAOB-deficient mice. Nat Genet. 1997;17(2):206-10.
Lindemann L, Hoener MC. A renaissance in trace amines inspired by a novel GPCR family. Trends Pharmacol Sci. 2005;26(5):274-81. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Phenethylamine (pea) and Gefitinib Together: Common Questions

Is it safe to take Phenethylamine (pea) with Gefitinib?

We do not list a known interaction between Phenethylamine (pea) and Gefitinib. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.

How was the Phenethylamine (pea) and Gefitinib combination checked?

Interactions in our licensed database are recorded against drug classes. Gefitinib is filed under 3 classifications, and Phenethylamine (pea) has documented interactions with 2 drug classes — none of Gefitinib's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.

Does Phenethylamine (pea) interact with any other medications?

Yes. Phenethylamine (pea) has 187 documented drug interactions in our database — Gefitinib is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

Does Gefitinib interact with any supplements?

Yes. Gefitinib has documented interactions with 168 supplements in our database — Phenethylamine (pea) is not one of them. The Gefitinib interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Phenethylamine (pea) monograph Uses, safety profile, and every drug interaction in one place Gefitinib drug information The full plain-English guide to this medication Gefitinib supplement interactions Every supplement checked against Gefitinib, 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 References The 9 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Gefitinib and Phenethylamine (pea)?

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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.