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

When your heart’s electrical cycle takes too long to reset after each beat, it’s called QT prolongation, a delay in the heart’s repolarization phase that can trigger life-threatening irregular heartbeats. Also known as long QT syndrome, it’s not always genetic — often, it’s caused by medications you’re already taking. This isn’t just a lab number. It’s a silent warning sign that could lead to torsades de pointes, a specific type of dangerous heart rhythm that can cause fainting, seizures, or sudden death. Many people don’t know they’re at risk until it’s too late.

Some of the most common drugs linked to QT prolongation include antipsychotics like risperidone, a medication used for schizophrenia and bipolar disorder that can disrupt heart rhythm, certain antibiotics like clarithromycin, and even some antidepressants. It’s not just about one drug — it’s about combinations. Mixing a QT-prolonging medication with a diuretic or an NSAID, for example, can push your heart over the edge. People with kidney disease, low potassium, or a history of heart problems are at higher risk. And yes, even over-the-counter cough syrups and antihistamines can be part of the problem.

QT prolongation doesn’t always cause symptoms, but when it does, you might feel dizzy, have palpitations, or pass out suddenly. If you’re on any of these medications and notice your heart skipping beats or feeling like it’s racing for no reason, don’t wait. Get checked. Doctors use EKGs to spot this issue before it turns deadly. The good news? Stopping the culprit drug or adjusting the dose often fixes it. But you need to know what you’re on — and why it might be dangerous.

Below, you’ll find real-world guides on medications that affect heart rhythm, how drug interactions make QT prolongation worse, and what to do if you’re taking antipsychotics, diuretics, or other high-risk drugs. These aren’t theoretical warnings — they’re based on actual cases and clinical guidance. Whether you’re a patient, caregiver, or just trying to understand your prescriptions, this collection gives you the facts you need to stay safe.