QT Prolongation: Risks, Medications, and What You Need to Know

When your heart’s electrical cycle gets thrown off, it can lead to something called QT prolongation, a delay in the heart’s repolarization phase that increases the risk of dangerous irregular heartbeats. Also known as long QT syndrome, it’s not always genetic—often, it’s triggered by everyday medications. This isn’t a rare side effect. It shows up in prescriptions you might not suspect, like certain antidepressants, antibiotics, and even some heart drugs. The problem? You won’t feel it until it’s too late.

Many of the drugs linked to QT prolongation are common. Citalopram hydrobromide, an antidepressant used for depression and anxiety, is one of the most well-documented offenders. Doses above 40 mg daily raise the risk significantly. Dextromethorphan, a cough suppressant found in many over-the-counter syrups, can also trigger it, especially when mixed with MAOIs. And it’s not just one drug at a time—combining two or more QT-prolonging meds multiplies the danger. This is why drug interactions matter more than most people realize. A simple cold remedy paired with an antidepressant can set off a chain reaction in your heart’s rhythm.

It’s not just about the pills you take. Your liver, kidneys, age, and even your genetics play a role. Someone with liver disease might process these drugs slower, letting them build up to dangerous levels. Older adults are more vulnerable. Women tend to have longer baseline QT intervals than men. That’s why a dose that’s safe for one person could be risky for another. Monitoring isn’t optional—it’s essential. If you’re on any of these meds and have a history of heart issues, dizziness, or fainting spells, talk to your doctor. A simple ECG can catch QT prolongation before it turns into torsades de pointes, a life-threatening arrhythmia.

The posts below dive into exactly this: how common medications interact with your heart’s electrical system, which ones to watch, and what to do if you’re at risk. You’ll find clear comparisons of drugs like citalopram, dextromethorphan, and carvedilol—not just as treatments, but as potential triggers. There’s no fluff. Just facts you can use to protect yourself or someone you care about.