Calan: What It Is, How It Works, and What You Need to Know

When your doctor prescribes Calan, a brand name for the medication verapamil, which is a calcium channel blocker used to treat high blood pressure and chest pain. Also known as verapamil, it works by relaxing blood vessels and slowing heart rate to reduce strain on your heart. Many people take Calan daily without issues, but others run into side effects like dizziness, swelling, or constipation—especially if they’re also on other heart meds.

Calan is one of several calcium channel blockers, a class of drugs that block calcium from entering heart and blood vessel cells, which helps lower blood pressure and control heart rhythm. Others in this group include amlodipine, diltiazem, and nifedipine. Each has slightly different uses: while Calan is often chosen for irregular heartbeats or angina, amlodipine might be picked for simpler high blood pressure cases. If you’ve tried one and it didn’t work—or caused too many side effects—there’s usually another option that fits better.

People taking Calan should be careful about what else they consume. Grapefruit juice can raise drug levels in your blood, making side effects worse. Some antibiotics, like clarithromycin, and even certain migraine meds can interact badly with it. If you’re on a beta-blocker too, your doctor needs to monitor your heart rate closely. And if you have liver problems, your dose might need to be lowered—Calan is processed through your liver, and slow processing means more drug stays in your system longer.

It’s not just about the pill. Managing high blood pressure or angina means watching your salt intake, staying active, and checking in regularly with your care team. Lab tests for liver function and heart rhythm are often part of the routine, especially if you’ve been on Calan for over a year. Some people find their symptoms improve so much they think they can stop—but quitting cold turkey can cause rebound high blood pressure or chest pain. Always talk to your doctor before making any changes.

Below, you’ll find real-world guides on how Calan compares to other heart meds, what to do if you miss a dose, how to spot dangerous interactions, and how to stay safe while managing long-term treatment. These aren’t generic advice pieces—they’re written by people who’ve lived with these conditions, tracked their labs, and learned what actually works.