Taking Melatonin With Hydroxyzine

In our latest question and answer, the pharmacist discusses whether or not there is a drug interaction between melatonin and hydroxyzine.

Taking Melatonin With Hydroxyzine
May 31, 2018

Jroberts320 asked

I was prescribed hydroxyzine 50mg for insomnia but I'm also on melatonin 5mg which wasn't working and my doctor didn't say anything about whether im supposed to stop taking the melatonin or not.


Melatonin bottleTaking hydroxyzine and melatonin together may cause added sedation, CNS effects, and respiratory depression. This could also cause unusual sleep-related behaviors or changes in mood or behavior. Since the melatonin didn’t seem to be effective, it may be best to discontinue the melatonin. If the hydroxyzine doesn’t work, discuss with your physician whether you should add the melatonin or try something else.


Information About Hydroxyzine

Hydroxyzine (Atarax) is a sedating antihistamine, also known as an H1-blocker.  Hydroxyzine has multiple effects including blocking the formation of itching, swelling, and flare related to histamine activity. Hydroxyzine can also reduce anxiety, nausea, and vomiting.

Hydroxyzine is absorbed quickly when taken orally and begins to work within 15 minutes to 1 hour. Typically, the duration of action lasts 4-6 hours. The half-life is about 14 to 25 hours. Hydroxyzine is metabolized in the liver to metabolites including cetirizine (Zyrtec) and norchlorcyclizine.

Hydroxyzine may cause dry mouth, blurred vision, constipation, and confusion.

Information About Melatonin

Melatonin is a hormone produced in the pineal gland that plays a role in the circadian rhythms of the body. Melatonin production is activated by darkness. Melatonin has been used off-label for many indications including insomnia, jet-lag, and shift work sleep disorder. Melatonin has also been used in hospital ICU patients to regulate sleep patterns.

Melatonin takes 15 minutes to 3.5 hours to reach maximum concentration. Taking with food can decrease absorption and may delay effect. Side effects include dizziness, abnormal dreams, and suicidal thoughts have been reported.  



  • Hydroxyzine and melatonin are generally not recommended to be taken together. This is due to the additive effects which may cause sedation, CNS side effects, and respiratory depression.
  • If hydroxyzine alone does not work to treat your insomnia, other alternatives may be considered including reintroducing melatonin. 

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