Drug & supplement interaction

Melatonin + Famotidine

Famotidine brand names: Pepcid, Famotidine, Pepcid AC, Famotidine Injection.

Moderate Interaction
Medically reviewed by · Updated October 2026
The bottom line Moderate

Melatonin has a moderate interaction with Famotidine. Theoretically, taking melatonin with drugs that lower the seizure threshold might increase the risk of seizure activity.

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

Melatonin and Famotidine

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

Moderate

SEIZURE THRESHOLD LOWERING DRUGS

Why this applies to Famotidine

Famotidine falls under SEIZURE THRESHOLD LOWERING DRUGS — the group Melatonin interacts with.

Theoretically, taking melatonin with drugs that lower the seizure threshold might increase the risk of seizure activity.
Some clinical evidence suggests that melatonin may increase the frequency of seizures in certain patients, particularly children with neurological disabilities.
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

Here's the honest picture: this isn't a drug-handling problem. Famotidine (Pepcid) is mostly cleared by your kidneys, not by the liver enzymes melatonin tends to bump into, so melatonin won't make famotidine build up or fade away. The flag here is something different. Famotidine sits in a broad group of medicines that, in rare cases, may slightly lower the seizure threshold, and there's a theory that melatonin could nudge seizure risk up in a small number of people.

For most folks taking famotidine for heartburn or reflux, this is a very low concern and based mainly on pharmacology, not strong studies. The signal is mostly seen in children with neurological conditions or people with a seizure history. If that describes you or your child, it's worth a quick chat with your pharmacist or doctor before adding melatonin.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Sheldon SH. Pro-convulsant effects of oral melatonin in neurologically disabled children. Lancet 1998;351:1254. PubMed
  2. Stewart LS. Endogenous melatonin and epileptogenesis: facts and hypothesis. Int J Neurosci 2001;107:77-85.. 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, 346 minor known drug interactions in our database — the Famotidine one above is one of them. If you take anything else, check it against the full list below.

Moderate 1,116 Minor 346 No known interaction 1,368 (incl. Famotidine)
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 Famotidine

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 Famotidine, 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 Famotidine

This page covers Melatonin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Famotidine page lists 41 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), African Wild Potato (moderate), Banderol (moderate), Beer (moderate) and Biofeedback (moderate).

By severity: 1 major · 19 moderate · 21 minor.

From our pharmacist’s overview on the Famotidine page

“Famotidine (Pepcid) treats heartburn and acid reflux, a low-stakes job most days, but its interaction list earns genuine caution because one entry is rated major. That entry is activated charcoal, which can bind famotidine in the gut and sharply cut how much of the drug reaches your blood.”

Reviewed by 2 · Jul 18, 2026

Open the Famotidine 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 Famotidine 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 Famotidine 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%

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

29 days ago today
Medication Famotidine
Top half

#739 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
Medication

About Famotidine

What Is Famotidine Used For?

Brand names: Pepcid, Famotidine, Pepcid AC, Famotidine Injection

Over-the-counter famotidine tablets (such as Pepcid AC, Acid Reducer and Acid Controller) relieve and prevent heartburn linked to acid indigestion and sour stomach. They can be taken to prevent heartburn brought on by certain foods and drinks.

Prescription famotidine treats active duodenal ulcer, active gastric ulcer, symptomatic nonerosive gastroesophageal reflux disease (GERD) and erosive esophagitis due to GERD. In adults, it also treats pathological hypersecretory conditions (such as Zollinger-Ellison syndrome) and lowers the risk of duodenal ulcer coming back. Famotidine for oral suspension is also used for peptic ulcer disease and GERD in children, and for GERD from birth. Famotidine Injection is for some hospitalized patients who cannot take oral medicine.

See full Famotidine drug information
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
346Minor
1,367No known interaction
1,116 Moderate 346 Minor 1,367 No interaction
Moderate

1,116 interactions

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

Minor

346 interactions

Showing 60 of 346 minor interactions — see all 346 on the Melatonin page.

No interaction 1,367 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 1,367 medications checked with no known interaction — see the full Melatonin list.

See the full Melatonin interactions page
See every supplement checked against Famotidine, 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 Famotidine supplement interactions › Every supplement checked against Famotidine, ranked by severity Famotidine drug information › The full plain-English guide to this medication 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 Famotidine Together: Common Questions

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

Still Have a Question About Famotidine 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.