Drug & supplement interaction

Melatonin + Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide

Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide brand name: Ascriptin Codeine #2.

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

Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide falls into 4 drug categories that Melatonin can interact with; the most serious is rated moderate. Theoretically, taking melatonin might increase the sedative effects of CNS depressants.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions4
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Melatonin and Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide

These two interact in 4 distinct ways. Each one is explained separately below.

Why Are There 4 Interactions?

Melatonin interacts with whole categories of medication. Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide falls into 4 of those categories, so it can interact with Melatonin in 4 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CNS DEPRESSANTS

1 of 4

Why this applies to Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide

Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide falls under CNS DEPRESSANTS — the group Melatonin interacts with.

Theoretically, taking melatonin might increase the sedative effects of CNS depressants.
Melatonin has sedative effects. Theoretically, concomitant use of melatonin with alcohol, benzodiazepines, or other sedative drugs might cause additive sedation.
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 combo product contains codeine, an opioid pain reliever that already makes a lot of people feel drowsy or foggy. Melatonin doesn't change how your body breaks codeine down, but it has its own gentle calming, sleepy effect. Stack the two together and those sleepy effects can simply add up, so you might feel more tired, more lightheaded, or slower to react than you'd expect.

To be clear, this is a theoretical caution based on how both work, not strong real-world data, and many folks use them together without trouble. Still, codeine can also slow your breathing, so be careful, especially the first night. Avoid alcohol, don't drive until you know how you feel, and check with your pharmacist or doctor before pairing them.

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
Moderate

SEIZURE THRESHOLD LOWERING DRUGS

2 of 4

Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide also falls under SEIZURE THRESHOLD LOWERING DRUGS.

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

This combo product mixes two antacids (aluminum and magnesium hydroxide), aspirin, and codeine for pain relief. The piece that interacts with melatonin here is the codeine. Strong opioids like codeine can, in higher doses, lower the seizure threshold, meaning they make seizures slightly easier to trigger. The concern on file is theoretical: in some people, especially children with neurological conditions, melatonin has been linked to more frequent seizures. Put the two together and there's a possible, small added risk.

For most healthy adults using this for short-term pain, this isn't a major worry, and the evidence is based on pharmacology and a few reports rather than solid studies. Still, if you have a seizure history or take this for a child, please check with your pharmacist or doctor before combining them.

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
Moderate

ANTICOAGULANT/ANTIPLATELET DRUGS

3 of 4

Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide also falls under ANTICOAGULANT/ANTIPLATELET DRUGS.

Theoretically, melatonin may have anticoagulant effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
There are isolated case reports of minor bleeding and decreased prothrombin activity in people taking melatonin with warfarin (Coumadin). The mechanism, if any, of this interaction is unknown. Taking melatonin orally seems to decrease coagulation activity within one hour of dosing in healthy men.
Severity Moderate Likelihood Possible Evidence B

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 combination product contains aspirin, which is the piece that matters here. Aspirin is itself a blood thinner (it makes your platelets less sticky), so it already nudges you toward easier bruising and bleeding. Melatonin may have a mild blood-thinning effect of its own, so pairing the two could, in theory, add up and slightly raise your bleeding risk.

To be honest, the evidence is thin and mostly theoretical, with only a few scattered reports. Still, watch for signs like easy bruising, nosebleeds, bleeding gums, or stomach upset, since aspirin can irritate the stomach too. If you take this regularly or have a bleeding history, check with your pharmacist or doctor before adding melatonin rather than changing anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev 2002;2:CD001520. PubMed
  2. Wirtz, P. H., Spillmann, M., Bartschi, C., Ehlert, U., and von Kanel, R. Oral melatonin reduces blood coagulation activity: a placebo-controlled study in healthy young men. J Pineal Res 2008;44(2):127-133. PubMed
  3. U.S.Food and Drug Administration. Special Nutritionals Adverse Events Monitoring System: registered case reports.
Minor

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

4 of 4

Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide also falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES.

Theoretically, melatonin might increase levels of drugs metabolized by CYP2D6.
Laboratory research suggests that certain lots of melatonin inhibit CYP2D6. Theoretically, combined administration of melatonin with certain drugs metabolized by the CYP2D6 enzyme 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 piece that actually matters in this combo product: the codeine. Codeine is a prodrug, meaning your body has to convert it into morphine using a liver enzyme called CYP2D6 before you feel real pain relief. Some lab studies hint that certain batches of melatonin might gently slow down that very enzyme. If that happened, less codeine would turn into morphine, so you could get weaker pain relief from this medicine.

The good news is this is a theoretical, minor concern based only on test-tube research, not real patients, so I wouldn't lose sleep over it. The aspirin and antacid parts aren't affected. Still, if your pain control feels off, mention it to your pharmacist or doctor before changing anything.

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 1,115 moderate, 345 minor known drug interactions in our database — the Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide one above is among them. If you take anything else, check it against the full list below.

Moderate 1,115 Minor 345 No known interaction 1,370 (incl. Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide)
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 Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide

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 Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide, 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 Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide

This page covers Melatonin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide page lists 339 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Asarabacca (major), Beer (major) and Danshen (major).

By severity: 11 major · 286 moderate · 42 minor.

From our pharmacist’s overview on the Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide page

“A person taking Ascriptin Codeine #2 for pain is getting aspirin, codeine, and two antacids in a single tablet, and the 339 supplement interactions on file deserve real attention before adding anything alongside it. Most of the list splits two ways.”

Reviewed by 2 · Jul 18, 2026

Open the Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide 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 Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide 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 Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide 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 Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide
Steady interest

#1,684 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
1,115Moderate
345Minor
1,369No known interaction
1,115 Moderate 345 Minor 1,369 No interaction
Moderate

1,115 interactions

Showing 60 of 1,115 moderate interactions — see all 1,115 on the Melatonin page.

Minor

345 interactions

Showing 60 of 345 minor interactions — see all 345 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 Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide, 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 Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide supplement interactions › Every supplement checked against Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide, 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 Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide Together: Common Questions

Can you take Melatonin with Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide?
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 4 interactions listed for Melatonin and Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide?
Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide belongs to more than one drug category, and Melatonin 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 Melatonin and Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide 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 Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide 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.