context: Drugs called beta-blockers perform four main tasks essential for people with heart failure: Improve your heart's ability to relax Decrease the production of harmful substances your body makes in response to heart failure Slow your heart rate Improve the heart's pumping ability over time If you have heart failure, you need beta-blockers -- even if you do not have symptoms. Beta-blockers are prescribed for patients with systolic heart failure and improve survival, even in people with severe symptoms. There are several types of beta-blockers, but only three are approved by the FDA to treat heart failure: Bisoprolol ( Zebeta) Carvedilol ( Coreg) Metoprolol ( Toprol) They may be taken with meals, at bedtime, or in the morning. Food delays how your body absorbs beta-blockers, but they also may reduce side effects. Follow the directions on the label. Beta-blockers shouldn't be used if you have very low blood pressure (hypotension) or a slow pulse (bradycardia) that may cause you to feel dizzy or lightheaded. If you have severe lung congestion, your doctor will treat your congestion before prescribing a beta-blocker. While you are taking this beta-blocker, your doctor may tell you to take and record your pulse daily. He'll tell you how rapid your pulse should be. If your pulse is slower than it should be or your blood pressure is less than 100, call your doctor about taking your beta-blocker that day. Never stop taking your medicine without speaking to your doctor first, even if you feel that it's not working. When you start taking beta-blockers, your heart failure symptoms may become a bit worse while your heart adjusts to the medication. This is normal, but let your doctor or nurse know if you become extremely tired, gain more than 5 pounds, have trouble breathing, or have other signs of congestion or swelling. Once your heart adjusts, you will feel better. Dizziness or lightheadedness: This may be strongest when you get out of bed or get up from a chair. Get up more slowly. Call your doctor or nurse if these symptoms don't go away or are severe. Tiredness, cold hands and feet, headache , nightmares , trouble sleeping, heartburn , diarrhea or constipation , or gas. Call your doctor or nurse if these symptoms don't go away or are severe. Sudden weight gain . Weight gain is common as your doctor increases your medication dose. Call your doctor if you gain 3 or more pounds in 1 day, or if you continue to gain weight for more than 2 days. Increased shortness of breath; wheezing ; trouble breathing; skin rash ; slow, fast, or irregular heartbeat ; swelling of feet and lower legs; chest pain . Call your doctor or nurse right away. Severe vomiting or diarrhea . If you have these, you may become dehydrated, which can lead to low blood pressure. Call your doctor or nurse. Also call your doctor or nurse if you have any other symptoms that cause concern. A beta-blocker is often prescribed with other medications such as a diuretic, ACE inhibitor, angiotensin receptor neprilysin inhibitor ( ARNI), or angiotensin receptor blocker ( ARB). If you have side effects after taking your medications together, call your doctor or nurse. You may need to change the times you take each drug. It's important that your doctor be aware of all the medications you are taking, as some may interact with beta-blockers. Talk to your doctor before taking any new drug, including over-the-counter drugs, herbs, and supplements.