Levocetirizine is a common antihistamine used to treat allergies like hay fever, hives, and itching. It’s sold under brand names like Xyzal and is often prescribed because it’s effective with fewer side effects than older antihistamines. But like any medication, taking too much can be dangerous. An overdose of levocetirizine doesn’t always cause dramatic symptoms right away-but when it does, it can be serious. Knowing the signs and what to do can make all the difference.
What Counts as a Levocetirizine Overdose?
The standard adult dose of levocetirizine is 5 mg once daily. For children, it’s lower-usually 2.5 mg daily for ages 6 to 11, and even less for younger kids. An overdose happens when someone takes more than the recommended amount, whether accidentally or intentionally. Taking 10 mg or more at once in an adult is considered potentially toxic. In children, as little as 5 mg can cause noticeable symptoms.
Most people who overdose don’t take 100 pills at once. More often, it’s a mix of mistakes: doubling up because symptoms didn’t go away, mixing it with other allergy meds, or giving a child the adult dose by accident. It’s also common for people to combine levocetirizine with other sedating antihistamines like diphenhydramine (Benadryl) without realizing the risk.
Common Symptoms of Levocetirizine Overdose
The body reacts to too much levocetirizine by slowing down central nervous system activity. Symptoms usually show up within 1 to 4 hours after ingestion. They can range from mild to life-threatening.
- Drowsiness - This is the most common sign. People may feel unusually sleepy, struggle to stay awake, or even fall into a deep sleep they can’t be woken from.
- Dizziness and loss of coordination - Walking may feel unsteady. People might stumble, slur their speech, or have trouble holding objects.
- Blurred vision - Vision becomes cloudy or double, making it hard to focus.
- Fast or irregular heartbeat - Levocetirizine can affect heart rhythm at high doses. This is especially risky for people with existing heart conditions.
- Dry mouth and flushed skin - The body’s ability to produce saliva and sweat decreases, leading to a parched mouth and red, warm skin.
- Nausea or vomiting - The stomach may react to the excess medication, though this isn’t always present.
- Seizures - Rare, but possible in severe overdoses, especially in children or people with epilepsy.
- Coma or respiratory depression - In extreme cases, breathing slows dangerously or stops. This is a medical emergency.
Children are more vulnerable. A 4-year-old who accidentally swallows two 5 mg tablets might become extremely drowsy, have trouble breathing, and need immediate medical help. Older adults are also at higher risk because their bodies process the drug slower.
What to Do If You Suspect an Overdose
If you or someone else has taken too much levocetirizine, don’t wait for symptoms to get worse. Time matters.
- Call emergency services - In Australia, dial 000. In the U.S., call 911. Tell them exactly what was taken, how much, and when.
- Do not induce vomiting - Unless a medical professional tells you to, don’t try to make the person throw up. This can cause more harm, especially if they’re already drowsy.
- Bring the medication bottle - When you get to the hospital, take the original packaging. It helps doctors know the strength, ingredients, and how much was in the bottle.
- Stay with the person - Monitor their breathing and level of consciousness. If they stop breathing, begin CPR if you’re trained.
Even if the person seems fine, don’t assume they’re out of danger. Symptoms can develop hours later. Some people feel okay after 2 hours, then suddenly become unresponsive.
How Hospitals Treat Levocetirizine Overdose
There’s no specific antidote for levocetirizine overdose. Treatment is supportive and focused on managing symptoms.
- Activated charcoal - If the overdose happened within the last hour, doctors may give activated charcoal to absorb the drug in the stomach before it enters the bloodstream.
- IV fluids - Helps flush the drug out and maintain blood pressure, especially if the person is dehydrated or has low blood pressure.
- Heart monitoring - Continuous ECG checks to watch for abnormal rhythms like QT prolongation, which can lead to dangerous arrhythmias.
- Respiratory support - If breathing is slow or shallow, oxygen or a ventilator may be used.
- Seizure control - Medications like benzodiazepines may be given if seizures occur.
- Observation - Most patients are kept in the hospital for at least 6 to 12 hours to make sure symptoms don’t return.
Most people recover fully with prompt treatment. The liver and kidneys clear levocetirizine over time, and once the drug is processed, symptoms fade. Recovery usually takes 1 to 2 days, depending on the dose and the person’s health.
Who’s at Highest Risk?
Some groups are more likely to have serious reactions:
- Children under 6 - Their bodies are smaller and less able to handle even small extra doses.
- Older adults (65+) - Slower metabolism and kidney function mean the drug stays in the body longer.
- People with kidney disease - Levocetirizine is cleared mostly by the kidneys. If they’re not working well, even normal doses can build up to toxic levels.
- Those taking other sedatives - Alcohol, sleep aids, opioids, or other antihistamines can multiply the effects.
- People with heart conditions - Especially those with long QT syndrome or previous arrhythmias.
How to Prevent an Overdose
Most overdoses are preventable with simple steps:
- Read labels carefully - Don’t assume all allergy meds are the same. Check for levocetirizine, cetirizine, or other antihistamines in combination products.
- Use a pill organizer - Especially helpful for people taking multiple medications daily.
- Keep meds out of reach - Store in locked cabinets, not on bathroom counters or kitchen tables where kids can grab them.
- Don’t mix with alcohol - Even one drink can make drowsiness much worse.
- Ask your pharmacist - If you’re unsure whether your other meds interact with levocetirizine, ask before taking them together.
- Set reminders - Use phone alarms to avoid accidentally taking a second dose.
Parents should treat allergy medicine like a controlled substance. A single extra tablet can land a child in the ER. Never use adult doses for children, even if they seem small.
When to See a Doctor After Taking Too Much
You don’t need to rush to the hospital for every accidental extra pill. But here’s when to get help:
- Any child under 12 who took more than the recommended dose
- Anyone who feels extremely drowsy, confused, or can’t be woken
- Anyone with a racing, fluttering, or irregular heartbeat
- Anyone having trouble breathing or fainting
- Anyone who took levocetirizine with alcohol or other sedatives
If you’re unsure, it’s always better to call a poison control center. In Australia, call 13 11 26. They’re available 24/7 and can guide you through what to do next.
Long-Term Effects After an Overdose
Most people who get treated quickly don’t have lasting damage. Levocetirizine doesn’t cause permanent organ injury in typical overdose cases. But repeated overdoses - especially in people with kidney problems - can lead to chronic issues.
People who overdose intentionally (like in a suicide attempt) need mental health support. Medication overdose is often a sign of deeper distress. Follow-up care with a counselor or psychiatrist is critical.
After recovery, doctors may recommend switching to a different allergy medication or lowering the dose, especially if kidney function is impaired.