Drug-Induced Arrhythmia: Causes, Risks, and Medications That Can Trigger It

When a medication changes your heart’s rhythm in a dangerous way, it’s called drug-induced arrhythmia, an abnormal heartbeat triggered by prescription or over-the-counter drugs. Also known as pharmacological arrhythmia, this isn’t rare—it happens more often than most people realize, especially with antibiotics, antidepressants, and heart meds. Your heart beats because of electrical signals, and some drugs mess with those signals, causing your heart to race, flutter, or skip beats. In worst cases, it can lead to sudden cardiac arrest.

One of the biggest culprits is moxifloxacin, a fluoroquinolone antibiotic linked to QT prolongation—a delay in the heart’s electrical recovery that sets the stage for dangerous rhythms. It’s not just antibiotics. Antidepressants like fluoxetine (Prozac), anti-nausea drugs like ondansetron, and even some allergy pills can do the same. Even common pain relievers like cetirizine have been flagged in rare cases. These aren’t random side effects—they’re predictable risks tied to how the drug interacts with ion channels in heart cells.

People with existing heart conditions, older adults, or those taking multiple drugs are at higher risk. But even healthy people can be affected if they’re on high doses or have genetic factors that slow how their body clears the drug. The good news? Many cases are preventable. Doctors check for QT prolongation before prescribing risky meds. Blood tests, EKGs, and knowing your full med list help catch problems early.

You won’t always feel it. Some people get dizzy or have palpitations. Others feel nothing until it’s too late. That’s why awareness matters. If you’re on a new drug and start feeling your heart race, skip, or pound for no reason, don’t ignore it. Talk to your doctor—don’t just stop the med on your own. A simple EKG can show if your heart’s electrical timing is off.

Below, you’ll find real-world guides on medications that can trigger these issues—from antibiotics like moxifloxacin to antidepressants like Prozac and even herbal supplements that may interact with heart drugs. We break down what to watch for, who’s most at risk, and how to protect yourself without giving up necessary treatments. This isn’t about fear—it’s about knowing the signs so you can act fast and stay in control.