Drug & supplement interaction

Melatonin + Trimetrexate Glucuronate

Trimetrexate Glucuronate brand name: Neutrexin.

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

Melatonin has a minor interaction with Trimetrexate Glucuronate. Theoretically, melatonin might increase levels of drugs metabolized by CYP3A4.

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

Melatonin and Trimetrexate Glucuronate

Here is the interaction we found between these two, with the evidence behind it.

Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Trimetrexate Glucuronate

Trimetrexate Glucuronate falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Melatonin interacts with.

Theoretically, melatonin might increase levels of drugs metabolized by CYP3A4.
Laboratory research shows that certain lots of melatonin inhibit CYP3A4. Theoretically, combined administration of melatonin with certain drugs metabolized by CYP3A4 may reduce the metabolism of these drugs, resulting in increased serum levels. Until more is known, use melatonin cautiously in patients taking drugs metabolized by these enzymes.
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

Here's the gist for Neutrexin (trimetrexate), a strong chemo-type medicine usually given in the hospital, often to treat serious infections like PCP pneumonia in people who can't take other options. Part of how your body clears trimetrexate runs through a liver enzyme called CYP3A4. Some lab studies suggest certain batches of melatonin can mildly slow that same enzyme down.

In theory, that could let trimetrexate build up a little, which might mean more of its known side effects, things like low blood counts, mouth sores, nausea, or liver irritation. I want to be honest though: this is only based on test-tube research, the concern is rated minor, and people on trimetrexate are already closely monitored. Still, mention any supplements, including melatonin, to your care team first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Foster BC, Cvijovic K, Boon HS, et al. Melatonin Interaction Resulting in Severe Sedation. J Pharm Pharm Sci 2015;18(2):124-31. 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

Melatonin Also Interacts With Other Medications

Melatonin has 1,116 moderate, 344 minor known drug interactions in our database — the Trimetrexate Glucuronate one above is one of them. If you take anything else, check it against the full list below.

Moderate 1,116 Minor 344 No known interaction 1,370 (incl. Trimetrexate Glucuronate)
Taking anything else?

Check Another of Your Medications Against Melatonin

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

From our Q&A

Questions About Melatonin or Trimetrexate Glucuronate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Melatonin or Trimetrexate Glucuronate, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Trimetrexate Glucuronate

This page covers Melatonin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Trimetrexate Glucuronate page lists 121 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate), Adrafinil (moderate) and African Wild Potato (moderate).

By severity: 2 major · 87 moderate · 32 minor.

From our pharmacist’s overview on the Trimetrexate Glucuronate page

“If you are being treated with trimetrexate glucuronate (Neutrexin), a medicine used against Pneumocystis pneumonia in people whose immune systems are already weakened, treat this list with real seriousness. Every one of the 121 supplements here interacts through the same liver enzyme, CYP3A4, which your body uses to clear the drug.”

Reviewed by 2 · Jul 18, 2026

Open the Trimetrexate Glucuronate interaction page

One more smart check

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

We hold 2,885 real supplement products containing Melatonin, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Melatonin. Your product may carry other ingredients that interact with Trimetrexate Glucuronate too, on top of Melatonin — 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 Melatonin and Trimetrexate Glucuronate 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 Melatonin
Top 5%

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

29 days ago today
Medication Trimetrexate Glucuronate
Steady interest

#2,696 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 Melatonin

What is Melatonin?

Melatonin
  • Trouble falling asleep (insomnia)
  • Jet lag
  • Delayed sleep phase syndrome
  • Non-24-hour sleep-wake disorder
  • Shift-work sleep problems
  • Sleep problems in some children with conditions like autism or ADHD

Melatonin is a hormone your body makes naturally to help control your sleep-wake cycle, and the supplement form is widely used to help with sleep timing problems and jet lag. The evidence is strongest for certain circadian (body-clock) disorders and is more mixed for everyday insomnia. It is generally well tolerated for short-term use, but talk with your pharmacist or doctor before starting, especially for children or during pregnancy.

Read the full Melatonin monograph & all interactions
Keep checking

Other Drugs & Melatonin

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

0Major
1,116Moderate
344Minor
1,369No known interaction
1,116 Moderate 344 Minor 1,369 No interaction
Moderate

1,116 interactions

Showing 60 of 1,116 moderate interactions — see all 1,116 on the Melatonin page.

Minor

344 interactions

Showing 60 of 344 minor interactions — see all 344 on the Melatonin page.

No interaction 1,369 drugs checked — show the list

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

Showing the 60 most looked-up of 1,369 medications checked with no known interaction — see the full Melatonin list.

See the full Melatonin interactions page
See every supplement checked against Trimetrexate Glucuronate, 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
Melatonin monograph › Uses, safety, and every drug interaction in one place Trimetrexate Glucuronate supplement interactions › Every supplement checked against Trimetrexate Glucuronate, 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 Melatonin and Trimetrexate Glucuronate Together: Common Questions

Can you take Melatonin with Trimetrexate Glucuronate?
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.
How serious is the Melatonin and Trimetrexate Glucuronate 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 Trimetrexate Glucuronate and Melatonin?

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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.