Long QT Syndrome: Causes, Risks, and Medications That Affect It

When your heart’s electrical cycle takes too long to reset, you might have long QT syndrome, a heart rhythm disorder that increases the risk of sudden, dangerous arrhythmias. Also known as QT prolongation, it can be inherited or triggered by certain drugs, electrolyte imbalances, or underlying heart conditions. This isn’t just a lab result—it’s a real threat that can lead to fainting, seizures, or even sudden death if not recognized.

Many medications listed in our posts can affect the QT interval, the time your heart takes to recharge between beats. Drugs like primaquine, an antimalarial known to cause hemolytic anemia in G6PD-deficient patients, or roxithromycin, a macrolide antibiotic linked to cardiac side effects, are known to stretch this interval. Even common drugs like compazine, an anti-nausea medication used in hospitals and clinics, carry warnings for people with existing heart rhythm issues. If you’re on any of these, or have a family history of unexplained fainting or sudden cardiac arrest, you need to know your risk.

It’s not just about the drug itself—it’s about combinations. A person taking nevirapine, an HIV medication that can cause liver toxicity and metabolic changes, along with a diuretic like amiloride, a potassium-sparing drug that alters electrolyte balance, might unknowingly stack risks. Low potassium, low magnesium, or dehydration can turn a mild QT prolongation into a life-threatening event. That’s why our collection includes detailed guides on drug interactions, safety during pregnancy, and how to spot early warning signs before it’s too late.

You’ll find real, practical advice here—not theory. We cover how specific drugs like long QT syndrome-triggering antibiotics, antifungals, and psychiatric meds interact with your heart. Whether you’re a patient managing multiple prescriptions, a caregiver, or a health professional checking for hidden risks, these posts give you the facts you need to act. No fluff. No jargon. Just clear connections between medications, heart rhythms, and what to do next.