Hydroxyzine For Sleep:
How An Antihistamine Can Relieve Insomnia

Hydroxyzine is an antihistamine, similar to Benadryl. It’s often prescribed by doctors to treat sleeplessness, especially insomnia resulting from anxiety.

It’s 2 A.M. and you’re lying in bed wide awake. You haven’t been able to get a truly restful night of sleep all week and you can feel your daytime hours suffering because of it.

Tomorrow is a busy day and you’re really becoming concerned with how you’re going to make it through without nodding off at your desk. You’re desperate for some sleep.

So what do you do?

For many people, situations like this mean turning to an antihistamine to get some shuteye. In fact, 1 in 5 adults regularly rely on over-the-counter sleep medication. And antihistamines are among the most commonly used.

Aleve PM, Unisom Sleep Tablets, and Nyquil all have antihistamine ingredients. And Benadryl, another antihistamine, is one of the most often used sleep aids- even by those who don’t suffer from any allergies at all.

But working your way through the drug store sleep isle isn’t always reliable or effective. In fact, despite your best efforts and countless purchases, you might still be awake.

When you’ve tried everything you can think of- from white noise to melatonin- it may be time to work with a doctor and see if a prescription sleep aid might be helpful to you.

Hydroxyzine, a prescription antihistamine, is one prescription your doctor may consider. Here, we’ll go over what you need to know about this medication and how it can help when insomnia won’t let you sleep.


Hydroxyzine’s Uses

Like we mentioned above, Hydroxyzine is an antihistamine- a type of medication that reduces the levels of histamine in the body.

Come again?

Histamine is a natural chemical produced in your body. When you experience an injury or allergic reaction, your cells release the chemical as a response.

Antihistamine medications help alleviate the symptoms that come along when histamine is released, like itching or skin rashes.

So primarily, these medications are used to treat allergic reactions and symptoms of allergies.

Hydroxyzine has also been shown to lessen activity in your body’s central nervous system. And because of that, doctors have found that it can be helpful in treating anxiety and insomnia.

Lastly because of its calming effects, Hydroxyzine is often paired with other medications and used for anesthesia.

When used to treat insomnia, it’s considered an off-label prescription. This means that, while a drug has been approved by the Food And Drug Administration, it hasn’t been approved for the reason a doctor is prescribing it to you.

In the case of this drug, the FDA has approved it for allergies but not insomnia.

Other off-label medications used by doctors for sleep include Trazodone and Doxepin.

There are two types of this medication: Hydroxyzine Hydrochloride (Atarax) and Hydroxyzine Pamoate (Vistaril). They work very similarly, though Vistaril is more commonly prescribed for anxiety and sleep.

It is not a controlled substance.


How Hydroxyzine Works

Antihistamines stop your body from producing the chemical histamine.

But how does this help with sleep?

It doesn’t per se. Its usefulness in treating insomnia actually comes from its drowsy side effects that cause sedation.

As with most other antihistamines available, including those over-the-counter, Hydroxyzine has a calming effect and can cause sleepiness.

More research is needed to understand exactly why this happens. But from what we understand, this type of medication suppresses activity in certain parts of your brain, providing a calming effect.

There’s also a direct link between histamine and your body’s sleep-wake cycle.

When histamine is released, it sends signals to your brain to wake up. And if you’re experiencing an increase in histamine at bedtime, you may have trouble falling asleep. So when antihistamines block the chemical release, your brain isn’t alerted with a wake-up signal.

This medication has been found to be most helpful as a short-term solution to acute insomnia, which is usually caused by a stressful life event. In fact, it’s not as effective of a solution when taken long-term.

Those who take their prescription for too long may build up a tolerance to the calming effect, and won’t be able to fall asleep. There is also some evidence that shows those who take this sleep aid for too long are at risk of not getting enough deep sleep, an essential stage in the sleep cycle.


How Long Hydroxyzine Lasts

Compared to other medications, it has a long half-life of 20 hours.

This means that after 20 hours, most people will have metabolized the medication to be half of its original concentration from when they took it.

The biggest concern with a long half-life like this is some of the medication’s effects may stick around. For example, some people may find that they wake up still feeling groggy.

In this case, your doctor may adjust your prescription dosage to help lessen or avoid this effect altogether. For some, this drowsiness may even disappear after a few days, even without a change in dose.

With this in mind, you should only take your prescription when you are able to get a full night of sleep. This means having 7-8 hours available for rest.

Hydroxyzine should only be taken before bedtime and you should never take it if you aren’t able to go to bed right away and stay asleep for at least 7 hours.

Finally, you should never operate a vehicle or other heavy machinery after taking your medication.


Hydroxyzine Dosage

The correct dosage of Hydroxyzine for sleep varies from person to person. And you’ll need to sit down with your doctor to figure out what’s appropriate for you.

For most, it’s prescribed between 10-50 mg and is taken once a day at bedtime. It’s likely your doctor will choose to start you off at a lower dose and may increase the dosage if needed.

Regardless of the dosage written for you, it’s important to take your medication exactly as your doctor has instructed. Do not take more or less than your prescription without first giving your doctor a call.

In addition to your prescription, your doctor will most likely provide you with sleep coaching. The idea here is to get to the root cause of what’s keeping you up at night and better prepare you for tackling poor sleep in the future.

Common sleep hygiene practices that are recommended include:

  • Limiting caffeine and alcohol intake, particularly close to bedtime
  • Incorporating regular exercise and activity into your day
  • Creating sleep schedules that include consistent sleep and wake times
  • Limiting the amount of time you spend in bed
  • Avoiding mid-day naps
  • Getting regular exposure to natural light


Hydroxyzine’s Side Effects

Though this medication is known to be an effective short-term aid for insomnia, some people may experience side effects.

As mentioned above, drowsiness is the most commonly reported adverse effect of this medication. And while that’s actually a benefit when you’re trying to fall asleep, it may affect some people later on in their day.

Drowsiness may go away after a few days or with an adjustment to your prescription dosage.

Other reported common side effects of Hydroxyzine include:

  • Fast or pounding heartbeat
  • Headache with chest pain
  • Severe dizziness
  • Fainting
  • Seizure
  • Skin redness or rash
  • Drowsiness
  • Headache
  • Dry mouth

Keep in mind this is not an exhaustive list of side effects. If you experience these or any other unusual or serious side effects, it’s important to reach out to a healthcare expert right away.

It’s also important to point out that drinking alcohol after taking a sleep aid can increase side effects.


Who Shouldn’t Use Hydroxyzine

Though this medication is often prescribed to those who are experiencing insomnia, it’s not the right sleep solution for everyone.

Let your doctor know if you have a history of any of the following medical conditions:

  • Personal or family history of long QT syndrome
  • Blockage in your digestive tract
  • Bladder obstruction or other urination problems
  • Glaucoma
  • Heart disease
  • Electrolyte imbalance
  • Pregnant, planning to become pregnant, or breastfeeding

This information is important for your doctor to know so that they can make a fully informed recommendation.

Additionally, it’s important to let your doctor know if you’re currently using any of the following:

  • Sleeping pills
  • Narcotic pain medication
  • Muscle relaxer
  • Medications for seizures
  • Antidepressants or benzodiazepines
  • Heart rhythm medication
  • Antipsychotic medicines
  • Medications to treat cancer, HIV, AIDS, or malaria

Always tell your healthcare provider about any prescriptions, non-prescription medications, supplements, vitamins, or herbal products you’re currently using regardless of whether or not they’re on the above list to avoid negative drug interactions.

This information will help make sure your doctor is creating a treatment plan that is most suited for you.



Hydroxyzine is a prescription antihistamine that has been shown to help in the treatment of insomnia, similarly to its over-the-counter counterparts. It’s most effective as a short-term solution for those experiencing acute insomnia that’s caused by a stressful life event, family matter, or personal life change.

If you suspect you have insomnia, seek medical advice from your doctor who can guide you through available treatment options. They’ll also work with you to rule out any other potential sleep disorders you might be experiencing, including sleep apnea.