Hydroxyzine Overdose: Symptoms, Treatment and Prevention

Last Updated: May 24, 2024

Dr. Norman Chazin Reviewed by Dr. Norman Chazin
0 sources cited

Overdose incidents have predominantly been associated with potent narcotics and street drugs, ignoring the potential risks posed by apparently benign medications, such as antihistamines.

In the U.S. alone, 92,033 overdose deaths reported during 2019–2020 were antihistamine-positive. Notably, first-generation H1 antihistamines, such as hydroxyzine, were implicated in nearly all these incidents. This data challenges the perception that only “hard” drugs can lead to overdose.

While it is widely used for its anti-allergy benefits, hydroxyzine overdose, whether through unintentional ingestion or deliberate self-harm, represents a severe reminder of the potential risks associated with its misuse. Continue reading to learn about safe dosing limits, overdose symptoms of hydroxyzine, and preventive measures.

Hydroxyzine Overview

Hydroxyzine is a prescription-only medication that belongs to a class of drugs known as first-generation antihistamines.

Unlike its newer counterparts, hydroxyzine crosses the blood-brain barrier and exerts a significant sedative effect. This makes it widely used not only for its antihistaminic properties but also for its effectiveness in reducing anxiety and tension. This medication works by blocking the action of histamine, a substance in the body that causes allergic symptoms.

Hydroxyzine is typically used for:

  • Relieving anxiety symptoms, such as nervousness, worry, and tension.
  • Treating itching caused by allergies.
  • Helping you sleep before surgery.

Hydroxyzine is available in several forms, including tablets (Atarax and Vistaril), capsules, syrup, and a solution for injection. Given its pharmacological profile, hydroxyzine is generally considered safe when used as prescribed. Taking too much hydroxyzine can lead to serious side effects, including overdose.

What is Hydroxyzine Overdose?

An overdose of hydroxyzine occurs when an individual consumes an amount of the drug that exceeds safe or prescribed levels, leading to a toxic reaction in the body. Given hydroxyzine’s role as a first-generation antihistamine with sedative properties, an overdose can result in pronounced central nervous system depression.

Unintentional vs. Intentional Vistaril Overdose

Overdoses can happen unintentionally, especially in children who might mistake the medication for candy or elderly people who are more susceptible to their anticholinergic and sedative properties. Intentional overdose might occur due to misuse or suicidal intent.

Severity of Vistaril Overdose

The severity of the overdose symptoms largely depends on the amount of hydroxyzine taken and whether it was ingested in combination with other substances (i.e., with alcohol or other CNS depressants) that can exacerbate the sedative effects, increasing the risk of a life-threatening overdose.

Hydroxyzine Overdose Side Effects

An overdose of hydroxyzine can lead to a range of side effects, which may vary in severity based on the amount ingested and individual risk factors for drug overdose, such as weight, polysubstance use, psychiatric comorbidity and overall health.

Recognizing these overdose side effects is crucial for timely intervention and management. The following are some of the common and severe side effects associated with an overdose of hydroxyzine, listed from most severe to less severe:

  • Severe pulmonary edema, hyperemia, and occasional alveolar hemorrhage (postmortem analysis)
  • Seizures
  • Respiratory depression
  • Hallucinations and delirium
  • Coma
  • Low blood pressure
  • Heart palpitations
  • Shortness of breath
  • Tremors
  • Fever
  • Skin reactions (rashes, lesions, swelling and redness)
  • Nausea and vomiting
  • Severe drowsiness
  • Dry mouth
  • Blurred vision
  • Ringing in the ears
  • Difficulty with urination
  • Sleeping difficulties
  • Agitation

Hydroxyzine can prolong the QT interval on an EKG (electrocardiogram), a measure of heart rhythm. In overdose, this effect can be exacerbated, leading to arrhythmias and other serious heart problems. If overdose symptoms of hydroxyzine are present, it is critical to seek medical attention immediately.

Hydroxyzine Overdose Dosage

The prescribed hydroxyzine dosage varies depending on its intended use, the patient’s age and overall health status. Understanding these dosages is crucial for recognizing when an overdose may have occurred.

Hydroxyzine dosage and administration should be as follows:

For Anxiety and Tension

  • Adults: 50 to 100 mg up to 4 times daily.
  • Children under 6 years: 50 mg daily, divided into smaller doses.
  • Children over 6 years: 50 to 100 mg daily, divided into smaller doses.

For Pruritus and Allergic Conditions

  • Adults: 25 mg 3 or 4 times daily.
  • Children under 6 years: 50 mg daily, divided into smaller doses.
  • Children over 6 years: 50 to 100 mg daily, divided into smaller doses.

As a Sedative (Premedication and Post-General Anesthesia):

  • Adults: 50 to 100 mg.
  • Children: 0.6 mg/kg.

Given these recommended dosages, an overdose might be suspected if an adult ingests significantly more than 400 mg in a day or if a child receives a dose much higher than their recommended daily maximum based on their age and weight.

Hydroxyzine Overdose: What to Do?

In the rare event of hydroxyzine (overdose, it’s essential to respond quickly and appropriately to ensure the safety and well-being of the patient.

Knowing the overdose symptoms can help better navigate the situation. Knowing the steps to take can be critical despite the rarity of such cases. Here are the general steps to follow in any potential overdose situation:

  • Dial 911 or your local emergency number for immediate medical assistance.
  • Contact the Poison Control Center at 1-800-222-1222 for guidance on what to do next.
  • Be prepared to provide details on the overdose, including dosage, timing and any other substances involved.
  • Unless instructed by a healthcare professional, do not try to induce vomiting.
  • Keep a close eye on the person’s symptoms development.

Hydroxyzine Overdose Treatment

Treatment for an overdose of hydroxyzine focuses on stabilizing the patient and managing symptoms. Given that there is no specific antidote for this overdose, treatment is mainly supportive and symptomatic.

Here is an overview of the approach generally taken in treating a hydroxyzine overdose:

  • Supportive care is needed to monitor vital signs, maintain airway and breathing, and manage seizures.
  • Medications to address issues like nausea or low blood pressure might be administered.
  • Stomach decontamination, probably with activated charcoal, to remove unabsorbed Hydroxyzine.
  • If the overdose was intentional, a psychiatric evaluation will be carried out.
  • Do not attempt to treat an overdose at home.
  • Bring any remaining Hydroxyzine medication with you to the hospital.
  • Follow doctors’ instructions carefully during recovery.

Most patients fully recover and are discharged, but high doses can lead to multiorgan failure in the elderly and children.

To ensure safe medication use and prevent overdose, take Hydroxyzine as prescribed by your doctor, never exceeding the recommended dosage. Store it securely in its original container in a cool, dry place out of reach of children and pets. Finally, properly dispose of unused or expired hydroxyzine medication, following your pharmacist’s guidance.

Hydroxyzine Overdose − Final Considerations

Hydroxyzine’s effectiveness is accompanied by a risk profile that demands caution. Remember that there is spectrum variability according to individual sensitivity, and even doses at the upper end of the recommended can trigger adverse effects, especially when mixed with other substances like alcohol.

Also, there is a potential for hydroxyzine misuse that may lead to abuse and dependency. For those struggling with hydroxyzine addiction, specialized treatments in rehabilitation facilities are available for those ready to recover. If you or someone you know is dealing with drug addiction, seeking professional help can be a critical first step towards healing.

People Also Ask

What happens if you overdose on hydroxyzine?

Overdosing on hydroxyzine can cause nausea, vomiting, drowsiness, confusion, and potentially seizures or heart problems. Seek medical attention immediately.

Can you die from a hydroxyzine overdose?

Deaths from an overdose of Hydroxyzine alone are rare, but severe overdose can lead to complications like breathing problems that may be fatal.

How much hydroxyzine to overdose?

Don’t rely on the maximum dosage for hydroxyzine. Take it exactly as prescribed to avoid overdose. Consult a doctor or pharmacist for safe dosage.

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Page Sources

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  2. National Institute of Diabetes and Digestive and Kidney Diseases. (2017b, January 16). Hydroxyzine. LiverTox - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK548128/
  3. Farzam, K., Sabir, S., & O’Rourke, M. C. (2023, July 10). Antihistamines. StatPearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK538188/
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  5. Lyons, R. M., Yule, A. M., Schiff, D., Bagley, S. M., & Wilens, T. E. (2019). Risk Factors for Drug Overdose in Young People: A Systematic Review of the Literature. Journal of Child and Adolescent Psychopharmacology, 29(7), 487-497. https://doi.org/10.1089/cap.2019.0013
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Published on: March 11th, 2020

Updated on: May 24th, 2024


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