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Can You Overdose on Hydroxyzine?
Yes, it’s possible to overdose on Hydroxyzine. Hydroxyzine overdose occurs when an individual takes more than the usual or recommended amount of the medication. This can be done by accident or intentionally.
Allergy medications like Hydroxyzine are safe when used correctly and can deliver quick relief from symptoms. However, an antihistamine overdose can be life-threatening, so understanding proper dosing is essential to avoid toxicity.
This drug shouldn't be used for more than 4 months. Contact your doctor if your symptoms don't improve in this timeframe.
What is Hydroxyzine (& What Does it Treat)?
Hydroxyzine Pamoate is in a class of medicines called antihistamines. It's a first-generation antihistamine with weak sedative, anticholinergic, and antiemetic properties.
It leads to sedation and breathing difficulties by inhibiting the hypothalamic H-1 histamine receptors involved in the sleep-wake cycle.
The drug is sold under the brand names Atarax and Vistaril. It’s available in the following forms:
- A suspension (to take by mouth)
What Does Hydroxyzine Treat?
Hydroxyzine blocks the action of histamine. This is a substance in the body that leads to allergic symptoms. It also decreases activity in the central nervous system (CNS).
Adults and children can take Hydroxyzine Pamoate for:
- Itch relief from allergic reactions on the skin, such as hives
- Medical condition treatment, like anxiety and tension in adults and children
- Sedation before and after general anesthesia for surgery (depresses the central nervous system (CNS)
Proper Hydroxyzine Dosage
Usually, Hydroxyzine is taken three or four times a day. Follow the directions on the prescription label correctly. Ask your doctor or a healthcare professional to explain any parts of the treatment you don’t understand.
Don’t consume more or less Hydroxyzine or take it more often than prescribed by your doctor. If you take Hydroxyzine by suspension, shake it well before use to mix the solution evenly.
Antihistamines like Hydroxyzine are safe when taken correctly.
Here are some tips and advice to avoid overdose:
- Don’t double up on doses
- Keep the drugs out of reach of children
- Do not take two doses too close together
- Ensure you read labels carefully
Hydroxyzine Side Effects & Risks
Taking Hydroxyzine may result in side effects and risks.
There are precautions for its use in:
- Pregnant women
- Those who have recently had a heart attack
- Those with slow or irregular heartbeats
- Those with glaucoma
- Those with low or high potassium levels
Speak with your doctor or a healthcare professional if any of the following symptoms are severe or persist after ingestion:
- Dry mouth
- Constipation (especially in older adults)
- Confusion (especially in older adults)
Some side effects can be more serious. They include:
- Unintentional trembling or shaking movements
- Pus-filled rash, blister-like sores or lesions
- Areas of redness or swelling on the skin
Let your doctor know about any abnormalities while taking this medicine. If you have glaucoma, you should also speak with your doctor before taking the drug.
Drugs to Avoid While Taking Hydroxyzine
Hydroxyzine can interact with other drugs you take. If you don’t know whether it’s safe to take Hydroxyzine with another medicine, speak with your doctor or a pharmacist.
Drug interactions may alter how your medications work or increase your risk for severe side effects. Keep a list of all the products you use and share it with your doctor or pharmacist. This includes prescription and non-prescription drugs and herbal supplements.
Don’t begin, stop, or alter the dosage of any medicines without a healthcare professional’s approval.
The following drugs may cause drowsiness, and you should tell your doctor or pharmacist if you are planning on taking them with Hydroxyzine:
- Opioid pain or cough relievers, such as codeine or hydrocodone
- Marijuana (cannabis)
- Medicines for sleep or anxiety, like alprazolam, lorazepam, or zolpidem
- Muscle relaxants, like carisoprodol or cyclobenzaprine
- Other antihistamines, like diphenhydramine or promethazine
- Drugs known to prolong QT interval
- Class III antiarrhythmics
- Some antimalarials (e.g., mefloquine)
- Some antibiotics (e.g., erythromycin, levofloxacin)
- Gastrointestinal agents (e.g., prucalopride)
- Anti-cancer drugs (e.g. toremifene, vandetanib)
Always check the disclaimer labels on your medications, especially allergy or cough-and-cold products. They may contain ingredients that lead to drowsiness.
Don't use Hydroxyzine with any other antihistamines applied to the skin, like diphenhydramine cream, ointment, or spray. This is because increased side effects could occur.
Symptoms of Hydroxyzine Overdose
Below is the full list of the vital signs of a Hydroxyzine overdose:
- Dilated pupils
- Shortness of breath
- Difficulty urinating
- Blurred vision
- Dry mouth
- Enlarged pupils
- Dry eyes
- Ringing in the ears
- Rapid heartbeat
- Low blood pressure
- Pounding heartbeat (palpitations)
- Lack of responsiveness
- Decreased level of consciousness
- Uncoordinated movement
- Dry, red, or flushed skin
How Long Do Overdose Symptoms Last?
It’s challenging to predict when an overdose may occur or how long it will last. The length of overdose symptoms depends on various factors, such as:
- How much Hydroxyzine was taken
- Your body weight
- Your size
If you are concerned about a potential overdose, seek medical attention immediately. Symptoms don't go away on their own. Overdoses are almost always fatal without proper help.
Is Hydroxyzine Overdose Dangerous?
Recovery from a Hydroxyzine overdose is likely if the person survives the first 24 hours.
However, the following complications may lead to permanent disability:
- Muscle damage from lying on a hard surface for an extended period
- Brain damage from a lack of oxygen
Few people die from an antihistamine overdose unless they have severe heart rhythm disturbances or breathing issues. However, there have been some deaths due to antihistamine toxicity. These include both accidental and intentional overdoses.
Deaths typically occur when a Hydroxyzine overdose leads to severe complications, including:
- Respiratory distress
- Cardiac arrest
Each individual has varied tolerance to antihistamines. However, toxicity typically occurs when a person consumes three to five times the recommended dosage.
When to Visit the ER
Some side effects and symptoms of taking antihistamines can mimic a drug overdose.
These side effects include:
- Mild nausea
- Stomach pain
These side effects don’t usually require medical attention. They may subside as your body adjusts to the medicine.
However, it’s always best to check with a doctor if you have side effects. You may need to adjust your dosage or take a different medicine.
The difference between side effects and an overdose is usually the severity of symptoms.
If someone is experiencing the following symptoms, they must visit the emergency room:
- Rapid heart rate
- Chest tightness
Before calling for emergency help, have the following information ready:
- The individual’s age, weight, and condition
- Name of the medication, including ingredients and strength if known
- Time the medicine was swallowed
- Amount of medicine swallowed
- Whether the medicine was prescribed for the individual
- If possible, bring the antihistamine product to the hospital with you
Antihistamine Overdose Treatment
Antihistamine overdose treatment works to stabilize the individual’s health and provides supportive care. The patient will likely receive activated charcoal in the hospital. This product is typically used in emergencies to help reverse the effects of drug poisoning.
Activated charcoal works as an antidote, stopping the absorption of toxins and chemicals from entering the body from the stomach. Toxins then bind to the charcoal and leave the body through bowel movements.
Tests that may be performed during an antihistamine overdose include:
- Blood and urine tests
- Chest x-ray ECG (electrocardiogram or heart tracing)
Other treatments may include:
- Fluids through a vein (by IV)
- Medications to treat symptoms
- Breathing assistance, including a tube through the mouth into the lungs and connected to a ventilator
Call to find out how much your insurance will cover
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- MedlinePlus. "Hydroxyzine overdose." 2021.
- Borowy CS, Mukherji P. "Antihistamine Toxicity." StatPearls Publishing, 2020.
- United States Food and Drug Administration. "FDA warns about serious problems with high doses of the allergy medicine diphenhydramine (Benadryl)." 2020.
- Randall, Katrina L, and Carolyn A Hawkins. “Antihistamines and allergy.” Australian prescriber, 2018.
- Church, Martin K, and Diana S Church. “Pharmacology of antihistamines.” Indian journal of dermatology, 2013.