Drug & supplement interaction

Melatonin + Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine

Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine brand name: Hycomine Compound.

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

Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine falls into 6 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
Interactions6
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Melatonin and Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine

These two interact in 6 distinct ways. Each one is explained separately below.

Why Are There 6 Interactions?

Melatonin interacts with whole categories of medication. Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine falls into 6 of those categories, so it can interact with Melatonin in 6 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 6

Why this applies to Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine

Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine 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 combination product (Hycomine Compound) is a mix of cold and pain relievers, but two ingredients matter most here: hydrocodone (an opioid) and chlorpheniramine (a sedating antihistamine). Both can make you sleepy on their own. Melatonin also nudges your body toward sleep, so stacking it on top could leave you feeling extra drowsy, foggy, or dizzy.

This is more of a theoretical concern based on how these ingredients work, not something proven to cause harm in studies. Still, with an opioid in the mix, I'd play it safe. Be careful with driving or anything where being alert matters, and check with your pharmacist or doctor before pairing the two, especially while you adjust.

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 6

Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine 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 combination cold and pain product (Hycomine Compound) carries a few ingredients, and a couple of them, the antihistamine chlorpheniramine and the opioid hydrocodone, can slightly nudge down your seizure threshold, meaning the brain becomes a touch more prone to a seizure. The concern here is mostly theoretical: melatonin has been linked, in a few reports, to more frequent seizures, especially in children with neurological conditions.

For most adults taking this medicine occasionally for a cold, this is a low-level worry. But if you or your child has epilepsy or any history of seizures, it is worth a quick chat with your pharmacist or doctor before pairing melatonin with this product. Also keep in mind the caffeine in it can work against the sleepiness you are using melatonin for.

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

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

3 of 6

Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine also falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES.

Theoretically, melatonin might increase levels of drugs metabolized by CYP1A2. Also, other CYP1A2 substrates might decrease the metabolism of melatonin, increasing melatonin levels.
Melatonin is metabolized in the liver primarily by the CYP2C19 and CYP1A2 enzymes. Theoretically, combined administration of melatonin with drugs metabolized by the CYP1A2 enzyme might reduce the metabolism of these drugs, resulting in increased serum levels. Conversely, some drugs metabolized by CYP1A2 may inhibit the metabolism of melatonin, resulting in increased serum levels of melatonin. Until more is known, use melatonin cautiously in patients taking drugs metabolized by these enzymes.
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

This combo product, sold as Hycomine Compound, is a real mix of ingredients. The one that overlaps with melatonin's pathway is the caffeine, which the body clears mainly through an enzyme called CYP1A2. On paper, melatonin might slow that enzyme a little, so caffeine could hang around longer than usual. If that happens, you might feel more of caffeine's effects: jitteriness, a racing heart, or trouble falling asleep (which works against the very reason you took melatonin in the first place).

To be honest, this is a theoretical concern based on how these substances behave, not something proven in real patients, so I wouldn't lose sleep over it. Just mention it to your pharmacist, especially since this product already has caffeine and a sedating ingredient together.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Yeleswaram, K., Vachharajani, N., and Santone, K. Involvement of cytochrome P-450 isozymes in melatonin metabolism and clinical implications. J Pineal Res 1999;26(3):190-191. PubMed
  2. Faber, M. S., Jetter, A., and Fuhr, U. Assessment of CYP1A2 activity in clinical practice: why, how, and when? Basic Clin Pharmacol Toxicol. 2005;97(3):125-134. PubMed
  3. 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

CAFFEINE

4 of 6

Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine also falls under CAFFEINE.

Theoretically, taking caffeine with melatonin might increase levels of melatonin.
Some evidence suggests that caffeine consumption can decrease endogenous melatonin levels, while other evidence suggests that caffeine increases endogenous melatonin levels. When administered in combination with melatonin supplements, caffeine seems to increase melatonin effects and levels. The reason for this discrepancy is not completely clear. Part of the discrepancy may result from the fact that caffeine can inhibit melatonin synthesis as well as inhibit melatonin metabolism. By functioning as an adenosine receptor antagonist, caffeine may indirectly inhibit the synthesis of melatonin. Conversely, because melatonin and caffeine are both metabolized by cytochrome P450 1A2 (CYP1A2) enzyme, concomitant use of melatonin and caffeine may reduce the metabolism of melatonin, resulting in higher serum levels.
Severity Moderate Likelihood Probable Evidence B

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 piece that matters: this combination product (Hycomine Compound) contains caffeine, and caffeine is the ingredient that interacts with melatonin. Both melatonin and caffeine are cleared by the same liver enzyme (CYP1A2). When you take them together, the caffeine can slow how fast your body breaks down melatonin, so melatonin levels may run a little higher and its sleepy, wind-down effect may feel stronger.

For most people this is mild and not dangerous. Just know it may make you a touch drowsier than usual, which can add to the sedating effects of the hydrocodone and chlorpheniramine already in this product. The evidence here is limited, so don't be alarmed, but since this product also contains an opioid, please run the combination by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Wright KP Jr, Myers BL, Plenzler SC, et al. Acute effects of bright light and caffeine on nighttime melatonin and temperature levels in women taking and not taking oral contraceptives. Brain Res 2000;873:310-7.
  2. Wright KP Jr, Badia P, Myers BL, et al. Caffeine and light effects on nighttime melatonin and temperature levels in sleep-deprived humans. Brain Res. 1997;747(1):78-84. PubMed
  3. Peuhkuri K, Sihvola N, Korpela R. Dietary factors and fluctuating levels of melatonin. Food Nutr Res. 2012;56. doi: 10.3402/fnr.v56i0.17252. Epub 2012 Jul 20. PubMed
  4. Babkoff, H., French, J., Whitmore, J., and Sutherlin, R. Single-dose bright light and/or caffeine effect on nocturnal performance. Aviat.Space Environ.Med. 2002;73(4):341-350.
  5. Ursing, C., Wikner, J., Brismar, K., and Rojdmark, S. Caffeine raises the serum melatonin level in healthy subjects: an indication of melatonin metabolism by cytochrome P450(CYP)1A2. J.Endocrinol.Invest 2003;26(5):403-406. PubMed
  6. Hartter, S., Nordmark, A., Rose, D. M., Bertilsson, L., Tybring, G., and Laine, K. Effects of caffeine intake on the pharmacokinetics of melatonin, a probe drug for CYP1A2 activity. Br.J.Clin.Pharmacol. 2003;56(6):679-682. PubMed
  7. Foster BC, Cvijovic K, Boon HS, et al. Melatonin Interaction Resulting in Severe Sedation. J Pharm Pharm Sci 2015;18(2):124-31. PubMed
Minor

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

5 of 6

Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine 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

This combination cold-and-pain product (Hycomine Compound) has a few moving parts, but the one that touches the CYP2D6 enzyme is the hydrocodone in it. Hydrocodone is partly a prodrug: your body uses CYP2D6 to turn some of it into hydromorphone, a stronger pain-relieving form. Lab research hints that melatonin might mildly slow CYP2D6. If that happened, it could shift how much active opioid you make, though the practical effect is hard to predict and likely small.

Honestly, this is a theoretical concern based only on test-tube data, rated minor. I would pay more attention to the simple fact that hydrocodone and chlorpheniramine both cause drowsiness, and melatonin adds to that sleepiness. Go easy and check with your pharmacist if you feel extra groggy.

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
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

6 of 6

Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

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

This combination product (Hycomine Compound) packs several ingredients, and one of them, hydrocodone, is partly processed by a liver enzyme called CYP3A4. In the lab, certain batches of melatonin have slowed that enzyme down a little. In theory, that could let hydrocodone build up slightly, which might mean a bit more drowsiness, dizziness, slowed breathing, or constipation. Keep in mind melatonin itself can make you sleepy, so the two together may feel extra sedating.

That said, this is rated a minor concern based only on test-tube data, not real patients, so for most people it is unlikely to cause trouble. Still, since this drug already contains an opioid, check with your pharmacist or doctor before pairing it with melatonin.

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 Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine 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. Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine)
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 Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine

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 Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine, 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 Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine

This page covers Melatonin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine 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 Ephedra (major).

By severity: 17 major · 276 moderate · 46 minor.

From our pharmacist’s overview on the Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine page

“If you've been prescribed Hycomine Compound (acetaminophen, caffeine, chlorpheniramine, hydrocodone, and phenylephrine) for a hard cough or cold, this list deserves real attention, since 17 of the 339 flagged supplements are rated major and most of those magnify what the medicine already does. Anything sedating, alcohol included, stack…”

Reviewed by 2 · Jul 18, 2026

Open the Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine 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 Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine 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 Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine 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 Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine
Top 25%

#412 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 Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine, 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 Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine supplement interactions › Every supplement checked against Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine, 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 Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine Together: Common Questions

Can you take Melatonin with Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine?
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 6 interactions listed for Melatonin and Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine?
Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine 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 Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, Phenylephrine 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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