Health January 21, 2026
Citalopram and Escitalopram: QT Prolongation Risks and Safe Dose Limits
QT Prolongation Risk Calculator
Antidepressant QT Prolongation Calculator
This tool estimates QTc prolongation risk based on FDA/MHRA guidelines for citalopram and escitalopram. For clinical decisions, always consult a healthcare professional.
When you’re prescribed an antidepressant, you’re usually focused on how it will help your mood, sleep, or anxiety. But there’s a quiet risk hidden in the fine print - one that can affect your heart, even if you feel fine. Two of the most common SSRIs, citalopram and escitalopram, carry a known, dose-dependent risk of QT interval prolongation. This isn’t theoretical. It’s backed by regulatory warnings from the FDA, MHRA, and other global agencies since 2011. And if you’re over 65, have heart issues, or take other meds, this risk isn’t something you can ignore.
What Exactly Is QT Prolongation?
Your heart beats because of electrical signals. The QT interval on an ECG measures how long it takes for your heart’s lower chambers to recharge between beats. If that interval gets too long, your heart can develop dangerous rhythms - like Torsade de Pointes - which can lead to fainting, seizures, or even sudden cardiac arrest.
Both citalopram and escitalopram block a specific potassium channel in the heart called hERG. That’s what slows down the recharging process. It’s not unique to these drugs - some antibiotics, antifungals, and older antidepressants do the same thing. But with SSRIs, the risk is dose-sensitive and predictable.
Citalopram: The Higher-Risk Option
Citalopram is a mix of two mirror-image molecules (enantiomers). Only one of them - the S-form - is active as an antidepressant. The other doesn’t help with depression, but it still affects your heart. That’s why citalopram carries a heavier cardiac burden than its purified cousin.
Here’s what the data shows:
- At 20 mg daily: QTc increases by about 8.5 milliseconds
- At 40 mg daily: QTc increases by 12.6 milliseconds
- At 60 mg daily: QTc increases by 18.5 milliseconds
That last number - 18.5 ms - is why regulators stepped in. The FDA and MHRA both flagged doses above 40 mg as unsafe. Why? Because at that level, the risk of crossing the 500 ms QTc threshold (the clinical danger line) becomes real, especially in older adults or people with other heart conditions.
Escitalopram: A Safer Alternative?
Escitalopram is just the active S-enantiomer of citalopram. No extra baggage. That’s why its cardiac effects are milder:
- At 10 mg daily: QTc increases by 4.5 milliseconds
- At 20 mg daily: QTc increases by 6.6 milliseconds
- At 30 mg daily: QTc increases by 10.7 milliseconds
Even at 30 mg - which is above the licensed maximum in most countries - escitalopram’s effect is still lower than citalopram at 40 mg. That’s why many clinicians now prefer escitalopram, especially for patients with heart disease, older adults, or those on multiple medications.
Dose Limits: What Regulators Say Now
After the 2011 safety reviews, every major health agency tightened the rules:
- Citalopram: Max 20 mg/day for patients over 65; max 40 mg/day for adults under 65
- Escitalopram: Max 10 mg/day for patients over 65; max 20 mg/day for adults under 65
These aren’t suggestions. They’re hard limits. Prescribing citalopram at 60 mg today would be considered off-label and potentially negligent. Even 40 mg of citalopram requires caution - and an ECG check if you have any risk factors.
Why the difference between countries? The UK’s MHRA took a broader view, warning about both drugs. The FDA focused mainly on citalopram. But the science is clear: both carry risk. The UK’s decision was more precautionary - and now, it’s the standard in most of Europe.
Who’s Most at Risk?
Not everyone on these drugs will have a problem. But certain people are far more vulnerable:
- People over 65 - metabolism slows, drugs build up
- Those with existing heart conditions - heart failure, prior arrhythmias
- Patients with low potassium or magnesium - electrolyte imbalances make QT prolongation worse
- People taking other QT-prolonging drugs - like certain antibiotics, antifungals, or anti-nausea meds
- Those with congenital long QT syndrome - rare, but life-threatening if missed
If you’re on citalopram or escitalopram and fall into any of these groups, your doctor should have already checked your ECG. If they haven’t - ask. It’s a simple, non-invasive test that takes five minutes.
How Do Other Antidepressants Compare?
Not all SSRIs are equal when it comes to heart risk:
- Fluoxetine, sertraline, paroxetine: Minimal QT effect - often safer choices
- Fluvoxamine: Slight risk, but less than citalopram
- Venlafaxine (SNRI): Low risk at normal doses, but dangerous in overdose
- TCAs (amitriptyline, maprotiline): Higher risk than SSRIs - avoid if possible in older adults
If you’ve been on citalopram for years and have no heart issues, you might be fine. But if you’re starting treatment now, and you’re over 60, have high blood pressure, or take a statin or diuretic - escitalopram at 10 mg is often the smarter first choice.
What About Long-Term Use?
Some worry that long-term use increases risk. But studies show the QT effect plateaus. It’s the dose, not the duration, that matters. A person on 20 mg of escitalopram for five years isn’t accumulating risk - they’re just on a stable, low-risk dose.
The bigger concern is combining these drugs with others. A patient on escitalopram 10 mg plus a common antibiotic like azithromycin? That combo can push QTc over 500 ms. That’s when things get dangerous.
What Should You Do?
If you’re taking citalopram or escitalopram, here’s what to do:
- Know your dose. Is it above the recommended limit? If yes, talk to your doctor.
- Ask if you’ve had an ECG in the last year - especially if you’re over 65 or on other meds.
- Don’t stop suddenly. Depression can worsen if you quit cold turkey.
- Report dizziness, palpitations, or fainting. These aren’t normal.
- Ask about alternatives. Sertraline or fluoxetine might be just as effective with less cardiac risk.
Most people on these drugs never have a problem. But when things go wrong, they go wrong fast. The goal isn’t to scare you - it’s to make sure you’re informed.
Bottom Line
Citalopram and escitalopram are effective antidepressants. But they’re not risk-free. Citalopram has a higher cardiac burden, especially above 40 mg. Escitalopram is safer, but still requires caution in older adults or those with heart conditions. Dose limits exist for a reason. They’re based on real data from thousands of patients. And if you’re on one of these drugs, you deserve to know how your heart is being affected - not just your mood.
Can citalopram cause sudden cardiac death?
Yes, but it’s rare. The risk is highest with doses above 40 mg daily, especially in people with existing heart conditions, low electrolytes, or those taking other QT-prolonging drugs. Torsade de Pointes, a dangerous heart rhythm, can lead to sudden cardiac arrest. Most cases happen in patients who were on high doses without proper monitoring.
Is escitalopram safer than citalopram for the heart?
Yes. Escitalopram causes less QT prolongation at equivalent doses because it doesn’t contain the inactive R-enantiomer found in citalopram, which contributes to cardiac risk. At 20 mg, escitalopram increases QTc by about 6.6 ms, while citalopram at the same dose increases it by over 12 ms. For patients with heart risks, escitalopram is usually the preferred SSRI.
Do I need an ECG before starting these medications?
It’s recommended if you’re over 65, have heart disease, take other medications that affect the heart, or have a history of fainting or irregular heartbeat. For healthy adults under 65 starting a low dose, routine ECG isn’t always required - but it’s still a good idea. Many doctors now order one as a baseline, especially with citalopram.
Can I take citalopram if I’m on a statin or diuretic?
It’s possible, but risky. Statins and diuretics can lower potassium or magnesium levels, which makes QT prolongation worse. If you’re on one of these, your doctor should check your electrolytes and consider switching to a safer antidepressant like sertraline. Never combine citalopram with a diuretic without monitoring.
What should I do if I feel my heart racing or fainting on this medication?
Stop taking the medication and seek medical help immediately. These could be signs of a dangerous heart rhythm. Don’t wait to see if it passes. Call your doctor or go to urgent care. Bring your medication list - including over-the-counter drugs and supplements - because interactions can trigger these symptoms.
Are there alternatives to citalopram and escitalopram with less heart risk?
Yes. Sertraline, fluoxetine, and citalopram’s cousin, fluvoxamine, have minimal QT effects. For many patients, sertraline is just as effective as escitalopram but carries less cardiac risk. If you’re over 65 or have heart disease, your doctor should consider these first. Cognitive behavioral therapy (CBT) is also a proven option - especially when combined with medication.
