Calcium channel blockers are a class of medications that help relax and widen blood vessels by preventing calcium from entering the cells of the heart and blood vessel walls. This action lowers blood pressure and reduces the workload on the heart, making them useful in treating conditions like hypertension and angina. These medications can also help manage certain heart rhythm disorders. Common examples of calcium channel blockers include amlodipine, diltiazem, and verapamil. While generally effective, they may cause side effects such as swelling, dizziness, or constipation, so it's important to use them under a doctor's guidance.