When your doctor says a drug is contraindication, a condition or factor that makes a particular treatment or procedure inadvisable. Also known as a drug warning, it’s not just a footnote—it’s a red light that could save your life. This isn’t about minor side effects. It’s about when mixing two things—like green tea and warfarin, or SAMe and antidepressants—can turn a safe treatment into a medical emergency. The FDA doesn’t list these randomly. Each one comes from real cases where people ended up in the hospital because someone didn’t know the risk.
Contraindications aren’t just about drugs interacting with other drugs. They’re about how your body reacts to them. Take narrow therapeutic index (NTI) drugs, medications where tiny changes in blood levels can cause toxicity or treatment failure. A generic version might look identical, but if your body absorbs it differently, your INR could spike or your seizure control could fail. That’s why therapeutic drug monitoring, regular blood tests to measure how much medicine is in your system is critical for people on drugs like warfarin or methotrexate. And it’s why pharmacists check your full list of meds—not just prescriptions, but supplements like SAMe or even green tea—before filling a bottle.
Some contraindications are obvious. Grapefruit and statins? Don’t mix. Others are sneaky. Proton pump inhibitors (PPIs) help prevent stomach bleeding in heart patients, but using the wrong type can block clopidogrel’s effect and raise your risk of a heart attack. Even something as simple as a pill organizer can become a problem if you’re taking multiple drugs with different timing needs. The point isn’t to scare you—it’s to make you ask the right questions. If you’re on more than one medication, you’re already playing a high-stakes game. Contraindications are the rules. Ignoring them isn’t bravery. It’s luck.
Below, you’ll find real stories from people who’ve been there. How green tea changed someone’s INR. Why a pharmacist flagged a generic that wasn’t working. What happens when you combine antidepressants with SAMe. These aren’t hypotheticals. They’re cases that happened to real people—and the lessons are clear: know your meds, ask before you mix, and never assume something is safe just because it’s natural or cheap.
1 Dec 2025
Understand key FDA drug label terms like contraindication, precaution, indications, and dosage to make safer medication decisions. Learn what each section means and how it protects patients.
