I Gave Our 5 Year Old Child Benadryl And Melatonin

In our latest question and answer, the pharmacist discusses whether or not it is safe to give Benadryl and melatonin to a 5-year-old.

3 min read Updated Jun 2026 Read by 10,102 people
I Gave Our 5 Year Old Child Benadryl And Melatonin
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Asp66 asked

I gave our 5-year-old Benadryl for allergies before dinner. Unknowingly, my husband gave him 1/2 a melatonin. Is this ok?

Sep 22, 2022
The quick answer
  • Taking Benadryl and melatonin together can cause extra drowsiness and should only be used together under a doctor's supervision for children.
  • A single accidental dose of both medications is unlikely to cause serious harm, but watch for any symptoms and contact Poison Control at 1-800-222-1222 if you notice anything concerning.
A quick summary of Dr. Brian Staiger, PharmD's full answer below, condensed by AI from that answer only (not from any outside source). The pharmacist's answer is the source of record.
Medications in this answer — tap to explore

Thanks so much for reaching out to us! Benadryl and melatonin should be used together with caution as the potential for additive sedative effects could be dangerous. For a five-year-old, these medications should only be taken together under the recommendation and supervision of a medical professional.

Nevertheless, a one-time dose of each isn't particularly worrisome, and as long as Benadryl was dosed according to the recommended instructions. There are unlikely to be any serious concerns like respiratory depression as this only occurs with high doses of Benadryl and is not typically associated with melatonin at all.

There may even be cases where your doctor recommends the combined use of melatonin and Benadryl, on a short-term basis. They work in different ways and don't necessarily interact with one another (aside from the additive sedation I mentioned).

What Is Benadryl?

Benadryl (diphenhydramine) is a sedating antihistamine used most commonly for the treatment of allergic reactions, seasonal allergies, symptoms associated with the common cold and insomnia. Benadryl may be taken without regard to meals. Commonly reported side effects associated with taking Benadryl include but are not limited to:

  • Drowsiness
  • Dizziness
  • Fatigue
  • Dry mouth

What Is Melatonin?

Melatonin is a naturally produced hormone that helps to regulate our circadian rhythm as well as the sleep-wake cycle. Although taking melatonin can help with making the body feel tired (as a rise of melatonin levels generally indicates to our body that it is time to sleep), it is not as effective as other treatments for short-term insomnia.

It is more effective in populations that have decreased melatonin production such as the elderly as well as populations that may have a disruption to the normal sleep-wake cycle such as shift workers or individuals suffering from jet lag.

Common side effects associated with taking melatonin include but are not limited to:

  • Drowsiness
  • Headache
  • Stomach cramps

Taking Benadryl And Melatonin In Children

As mentioned above, it generally isn't recommended to give sedating antihistamines, like Benadryl, with melatonin. The combination may result in additive sedation and potentially more serious effects, although they are uncommon.

Melatonin itself, with short-term, intermittent dosing, doesn't have frequent or pronounced CNS (central nervous system) effects as Benadryl does. Taking it with Benadryl, we are more concerned with prolonged sedation and drowsiness, especially during waking hours. This is sometimes known as a "hangover" effect.

A one-time, accidental dose of Benadryl and melatonin is not likely to cause serious medical concern. However, if any issues or noticeable symptoms arise, it would be prudent to go to the emergency room or call Poison Control at 1-800-222-1222. Final Words

Thanks again for reaching out and please feel free to do so again anytime!

References & sources
  1. Diphenhydramine Monograph — PubChem
  2. Melatonin Monograph — PubChem
  3. Insomnia in childhood and adolescence: clinical aspects, diagnosis, and therapeutic approach — PubMed
Glossary — Terms in This Answer
Antihistamine
A medication that blocks histamine, a chemical in the body that causes allergic reactions and inflammation.
Additive sedative effects
When two or more drugs that make you drowsy are combined, their combined effect is stronger than either drug alone.
Respiratory depression
A dangerous slowing of breathing that can occur with certain medications, especially at high doses.
Diphenhydramine
The active ingredient in Benadryl, a type of antihistamine used to treat allergies and sleep problems.
Circadian rhythm
Your body's natural 24-hour cycle that controls sleep, wake times, and other body functions.
CNS (central nervous system) effects
Changes in how the brain and spinal cord function, such as drowsiness, dizziness, or confusion.
Sedating
Causing drowsiness or sleep.
Hangover effect
Prolonged drowsiness or grogginess that continues after a medication's main effects should have worn off.
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Dr. Brian Staiger, PharmD
About the pharmacist

Dr. Brian Staiger, PharmD

Clinical Pharmacy

Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified

Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...

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