QT Prolongation: Risks, Medications, and How to Stay Safe

When your heart’s electrical cycle takes too long to reset, it’s called QT prolongation, a delay in the heart’s repolarization phase that can trigger dangerous irregular heartbeats. Also known as long QT syndrome, it’s not always genetic—many cases are caused by everyday medications. This isn’t just a lab result; it’s a real risk that can lead to torsades de pointes, a type of arrhythmia that may cause sudden collapse or death if untreated.

Many common drugs can cause QT prolongation, including certain antibiotics like azithromycin, a widely prescribed antibiotic linked to heart rhythm changes, antidepressants like citalopram, an SSRI that carries warnings for cardiac effects at higher doses, and even some anti-nausea meds like ondansetron, a drug often used after surgery or chemotherapy that can interfere with heart electrical activity. The risk goes up if you’re on more than one of these, have low potassium or magnesium, or already have heart disease. It’s not rare—studies show over 100 medications carry this risk, and many people don’t know they’re taking one.

It’s not just about avoiding bad combos—it’s about timing, dosage, and monitoring. Some people need an ECG before starting certain drugs. Others need blood tests to check electrolytes. Even something as simple as skipping a meal or taking a diuretic can lower potassium enough to push someone into danger. You don’t need to panic, but you do need to ask: Could this medicine affect my heart? The posts below cover real cases where QT prolongation happened, which drugs are safest to use together, how to spot early signs like dizziness or palpitations, and what to do if you’re on multiple prescriptions that could interact. You’ll find practical advice on checking your meds with interaction tools, understanding when to push back on a prescription, and how to talk to your pharmacist about hidden risks. This isn’t theoretical—it’s about keeping your heart safe while still getting the treatment you need.