Hydroxyzine and QT Prolongation: What You Need to Know About the Cardiac Risk

Hydroxyzine has been used for decades to treat anxiety, itching, and nausea. It’s cheap, effective, and widely prescribed - especially in older adults and people with chronic skin conditions. But behind its calming reputation lies a quiet, dangerous risk: hydroxyzine can mess with your heart’s electrical system and trigger a life-threatening rhythm called Torsade de Pointes. This isn’t a rare rumor. It’s a documented, FDA-recognized danger that’s changed how doctors prescribe this drug - and you need to know if you’re at risk.

How Hydroxyzine Affects Your Heart

Hydroxyzine works by blocking histamine receptors, which reduces itching and calms anxiety. But it doesn’t stop there. It also blocks something called the hERG potassium channel in heart cells. This channel helps your heart reset after each beat. When it’s blocked, the heart takes longer to recharge - and that’s called QT prolongation. On an ECG, it shows up as a stretched-out interval between the Q and T waves. That’s not just a number on a graph. It’s a warning sign that your heart could suddenly go into a dangerous, chaotic rhythm.

It doesn’t happen to everyone. But when it does, it can be fatal. Torsade de Pointes isn’t a slow, predictable arrhythmia. It comes on fast - sometimes within 10 minutes of taking a dose. People have collapsed, gone into cardiac arrest, and needed emergency defibrillation after just one 25 mg tablet. The risk isn’t linear. A healthy 30-year-old might take 100 mg without issue. But someone over 65, with low potassium, on other heart meds, or with a genetic predisposition? That same dose could be deadly.

The Evidence Isn’t New - It Was Ignored

For years, hydroxyzine was considered safe because it’s an antihistamine. Doctors assumed, like with diphenhydramine or loratadine, that it was harmless to the heart. But that changed in 2015. The European Medicines Agency reviewed over 60 years of data and found 59 confirmed cases of QT prolongation or Torsade de Pointes linked to hydroxyzine. Before that, there were only a handful of case reports. Now, we know it’s not rare - it’s underreported.

The FDA added hydroxyzine to its official list of drugs with QT prolongation risk in 2019. That’s not a footnote. It’s a red flag. The EMA responded by slashing the maximum daily dose from 200 mg to 100 mg for adults and cutting it to 50 mg for people over 65. They didn’t pull it off the market - they just made it clear: this isn’t a drug you can hand out like a vitamin.

Who’s at Real Risk?

Hydroxyzine isn’t dangerous for everyone. But it’s extremely dangerous for certain groups. Here’s who needs to avoid it:

• People with a QTc interval over 450 ms (men) or 470 ms (women) - confirmed by ECG
• Those taking other QT-prolonging drugs like amiodarone, citalopram, or certain antibiotics
• Patients with low potassium (under 4.0 mmol/L) or low magnesium (under 1.8 mg/dL)
• People with heart failure, bradycardia (heart rate under 50), or structural heart disease
• Adults over 65 - especially if they’re on multiple medications
• Those with CYP2D6 poor metabolizer genetics - which slows drug clearance and raises blood levels
• Dialysis patients - who often have electrolyte imbalances

Here’s the kicker: a 2021 survey of 127 hospital pharmacists found that 63% had seen hydroxyzine prescribed to patients with two or more of these risk factors - even when hospital rules banned it. That’s not a mistake. It’s a pattern. And it’s killing people.

What Happens When You Take It Anyway?

Case reports tell the real story.

In 2022, a 68-year-old woman with no heart history took 50 mg of hydroxyzine for anxiety. She’d also been on amiodarone for years. Within 12 hours, she went into Torsade de Pointes. She needed emergency cardioversion. She survived - but barely.

In another case, a 45-year-old man had mild itching. He took 25 mg of hydroxyzine - half the max dose. Fifteen minutes later, he passed out. He had undiagnosed long QT syndrome. He didn’t know he was at risk. His doctor didn’t check.

On Reddit, over 19 users reported palpitations, dizziness, or fainting within an hour of taking hydroxyzine. These aren’t coincidences. These are early warning signs. And they’re being ignored.

How Prescribing Has Changed - and What You Should Expect

Hospitals and clinics are finally catching up. Electronic health records now block hydroxyzine orders if a patient has a QTc over 500 ms or is on another high-risk drug. Pharmacists are trained to flag it. Some institutions require a signed consent form acknowledging the cardiac risk.

But the biggest change? ECGs are no longer optional. If you’re over 50, have heart disease, or are on other meds, your doctor should order a baseline ECG before prescribing hydroxyzine. If your QTc is borderline, they might repeat it after a few days. That’s not overkill - it’s standard care now.

And dosing? Stick to the limits: 100 mg max for adults, 50 mg for seniors. Never take it daily for weeks. It’s meant for short-term use - a few days for anxiety before a procedure, or a week for severe itching. Chronic use? That’s where the risk spikes.

What Are the Safer Alternatives?

You don’t need hydroxyzine. There are better options.

• For anxiety: Buspirone, SSRIs like sertraline, or even low-dose benzodiazepines (with caution) are safer for the heart.
• For itching: Cetirizine or loratadine - second-gen antihistamines - have almost no QT effect. Gabapentin is now preferred for chronic pruritus, especially in older adults.
• For sleep: Mirtazapine has replaced hydroxyzine in many geriatric clinics. It’s sedating but doesn’t prolong QT.

Even diphenhydramine (Benadryl) is a better choice than hydroxyzine if you need an antihistamine - though it still carries some risk. The bottom line: don’t reach for the first-gen antihistamine. Go for the safer ones.

What If You’re Already Taking It?

If you’ve been on hydroxyzine for months - even at low doses - stop panicking. But do this:

1. Check your current dose. Is it over 50 mg/day if you’re over 65? If yes, talk to your doctor.
2. Review your other meds. Are you on any antibiotics, antidepressants, or heart drugs? Use the CredibleMeds database to check interactions.
3. Ask for an ECG. If you’ve never had one, get one now. It’s quick, painless, and could save your life.
4. Watch for symptoms: dizziness, palpitations, fainting, or sudden fatigue. If you feel any of these after taking it, stop and call your doctor.
5. Don’t stop abruptly if you’re using it for anxiety. Talk to your provider about tapering.

Hydroxyzine isn’t a drug you should be on long-term. It was never designed for that. And now, we know why.

The Future: Is Hydroxyzine Going Away?

No - but its role is shrinking. U.S. prescriptions dropped from 18.3 million in 2014 to 12.7 million in 2022. That’s a 30% decline - and it’s still falling. The American Geriatrics Society now lists it as a potentially inappropriate medication for older adults. The European Society of Cardiology is expected to ban chronic prescribing by 2025.

Meanwhile, researchers are working on a new version - VH-01 - designed to keep the antihistamine effect but ditch the hERG blockade. Early trials show it’s 87% safer for the heart. That’s the future. But for now, hydroxyzine is a relic with a dangerous shadow.

The message isn’t to fear hydroxyzine. It’s to respect it. It’s not a casual sedative. It’s a drug that demands a heart check before every prescription. If your doctor doesn’t ask about your ECG, your meds, or your electrolytes - ask them why. Your heart is worth the question.