8/18/2012 1:35:00 PM Dr. K for August 19, 2012 Side effects of beta blockers can be controlled
DEAR DOCTOR K: My doctor wants me to take a beta blocker for my high blood pressure. Can you tell me about these drugs?
DEAR READER: Beta blockers are one of the most important classes of drugs invented in the past half-century. In fact, they are so important that their inventor, Sir James Black, was honored with the Nobel Prize. They have saved many lives -- but that doesn't mean they are for everyone, or without possible side effects.
Beta blockers are primarily used to control high blood pressure (hypertension) and abnormal heart rhythms. They are also used to prevent further heart problems in patients who have had heart attacks or who have heart failure. It's not uncommon for a person to have hypertension and abnormal heart rhythms along with heart attacks or heart failure in the past. So some people get multiple simultaneous benefits from beta blockers.
Beta blockers lower blood pressure primarily by slowing the rate and the force with which the heart pumps. They do this by blocking the hormones norepinephrine and epinephrine. Both hormones can accelerate your heart rate. After being used for a long time, beta blockers also tend to relax blood vessels.
There are three types of beta blockers. Some are longer-acting; some enter the brain more easily; and some are called cardioselective and affect primarily the heart, not the lungs. The type of beta blocker your doctor prescribes will depend on your particular medical needs. (I have a list of the different types of beta blockers on my website.)
Since you're new to beta blockers, let your doctor know if you think you may be having any side effects. Some people taking beta blockers complain of fatigue. Lightheadedness from a drop in blood pressure is also a risk. Erectile dysfunction is another possible side effect.
Beta blockers can sometimes cause wheezing, particularly in people with asthma. In people with diabetes on blood sugar-lowering medicines, being on a beta blocker can sometimes mask the symptoms of low blood sugar.
These side effects often can go away with adjustments to the dose of the beta blocker or switching to another type. For example, if you have wheezing, you can be switched to a beta blocker that affects mainly the heart but not the lungs.
We have more information on drugs that lower high blood pressure in our Special Health Report, "Hypertension." (Learn more about this report at AskDoctorK.com, or call 877-649-9457 toll-free to order it.) Even if you experience side effects, do not stop taking beta blockers without first checking with your doctor. Suddenly stopping them might cause an unsafe rise in blood pressure or a worsening of angina.
Beta blockers were first introduced at about the time I started my medical practice. I'm glad I have had these medicines available to help my patients throughout my whole career.
(Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.)