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

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—often, it’s caused by everyday medications.

This isn’t just a lab result. Torsades de pointes, a life-threatening type of irregular heartbeat linked directly to QT prolongation can strike without warning. It’s why doctors check your ECG before prescribing certain antibiotics, antidepressants, or antipsychotics. Drugs like azithromycin, a common antibiotic sometimes used for respiratory infections, and sertraline, an SSRI antidepressant widely prescribed for anxiety and depression, are known to carry this risk, especially when combined with other meds or in people with existing heart conditions. Even over-the-counter cold remedies and some antihistamines can nudge your QT interval out of safe range.

It’s not about avoiding all meds—it’s about awareness. If you’re on multiple prescriptions, have a history of heart issues, or notice sudden dizziness, palpitations, or fainting spells, your QT interval might be the hidden cause. People with low potassium or magnesium, older adults, and women are at higher risk. The good news? Most cases are reversible if caught early. Your doctor can adjust your meds, order a quick ECG, or recommend supplements to balance electrolytes.

The posts below dive into real-world examples: how antibiotics like Zithromax can affect heart rhythm, why certain antidepressants and antipsychotics need careful monitoring, and how liver or kidney problems can make QT prolongation worse. You’ll find clear comparisons of drugs that carry this risk versus safer alternatives, plus practical tips on spotting early signs before it becomes an emergency. This isn’t theoretical—it’s about making sure your next prescription doesn’t put your heart in danger.