Macrolide antibiotics like azithromycin and clarithromycin can cause dangerous heart rhythm changes called QT prolongation, especially in older adults, women, or those on other medications. Know your risk factors and ask for an ECG before taking them.
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—many cases are caused by everyday medications. This isn’t just a lab finding. It’s a real, life-threatening condition that can lead to torsades de pointes, a specific type of chaotic heart rhythm that can cause fainting, seizures, or sudden death if not caught early.
Drugs linked to QT prolongation aren’t rare. They include common antibiotics like azithromycin, antidepressants like citalopram, antifungals like itraconazole, and even some anti-nausea meds. Even over-the-counter antihistamines can do it in sensitive people. The risk goes up if you’re on more than one of these drugs, have low potassium or magnesium, or already have heart disease. It’s not about being weak—it’s about how your body processes these chemicals. Some people clear them fast. Others hold onto them longer, turning a normal dose into a ticking time bomb.
Doctors don’t always check for QT prolongation unless you’re on high-risk meds or have symptoms like dizziness, palpitations, or unexplained fainting. But if you’re taking anything for ADHD, depression, infection, or even acid reflux, it’s worth asking: could this be affecting my heart’s rhythm? The good news? It’s often reversible. Stop the drug, correct electrolytes, and the heart usually resets. The bad news? If it’s missed, it can kill you in minutes.
What you’ll find below are real, practical guides from doctors and pharmacists who’ve seen this play out. From how QT prolongation connects to common prescriptions like those for ADHD or fungal infections, to how generic drugs can carry the same hidden risks as brand names—this collection cuts through the noise. You won’t find theory here. Just clear, actionable info on which meds to watch, what tests to ask for, and how to protect yourself before it’s too late.