Adrenaline is often a welcome boost of energy, but for people with heart conditions, the effects of adrenaline can worsen how their body feels. Blocking the effects of adrenaline has been known to improve their conditions.

Beta blockers, also known as beta adrenergic blocking agents, are a class of drug that obstructs the effects of adrenaline. Doctors prescribe these blocking agents to treat a variety of heart ailments including high blood pressure, irregular heart rhythm (arrhythmia), heart failure, chest pain (angina), and heart attacks.

Your doctor might also use beta blockers to treat glaucoma, anxiety disorders, hyperthyroidism, migraine, and certain types of tremors. Often they are prescribed as part of a larger treatment plan.

Only some people are good candidates for beta blockers. This depends on the disease in question, that person's general health, and his or her response to the drug.

Beta blockers stop the effects of adrenaline from working on your heart. Adrenaline is a stimulating hormone that can increase heart rate, heart contractions, and electrical conduction.

Beta blockers allow the heart to relax. By reducing heart rate, they can improve the heart’s pumping ability over a period of time. A slower heart rate also reduces blood pressure, opens blood vessels, and in turn helps blood flow more easily to tissues and organs. In patients with history of heart failure, they can also reduce the body's production of harmful substances.

Because of their tremendous impact on the heart, beta blockers are often prescribed to treat chest pain (whether after exertion or while at rest), high blood pressure, increased heart rate, arrhythmia, and heart failure.

Examples of some beta blockers include:

• Acebutolol

• Atenolol

• Bisoprolol

• Carvedilol

• Metoprolol

• Nadolol

• Nebivolol

• Propranolol

Always follow directions on the drug label for taking beta blockers.

You should take this medication with meals, either in the morning or evening. The body absorbs the drug more slowly when taken with food, and that extra time can help reduce unwanted side effects. The number of doses, time between taking doses, and length of treatment varies with individuals, so for details about your specific treatment, consult your physician.

Beta blockers should be taken the same time each day. Take a missed dose as soon as you remember, but if four to six hours have passed, skip it – do not take that forgotten dose.  Also, you should not take two doses at once to make up for a missed dose. 

Use with Caution: Asthma and Diabetes

If you have asthma or other lung problems, such as chronic obstructive pulmonary disease (COPD), your physician might avoid giving you a beta blocker. People with these lung conditions can suffer because beta blockers might narrow their breathing airways, which can trigger or worsen an asthma attack. If you do have to take the drug, there is a need for close monitoring. Your physician can also help you by prescribing a newer type of beta blocker, which impacts the heart without affecting airways.

Patients with diabetes or raised blood sugar should know that beta blockers are not the best choice of treatment.  Beta blockers block the rapid, pounding heartbeat that is often a diabetic's first indication something is wrong.  Additionally, by blocking adrenaline, they are also stopping the release of stored sugar into the blood stream during these diabetic episodes. 

Other patients who should probably avoid beta blockers include people with low heart rate, poor circulation in hands and feet, thyroid/kidney/liver disease, and allergies to foods or dyes. You should also inform your doctor if you are planning to start a family, or are pregnant or breast-feeding.

It is rare that someone experiences side effects from beta blockers. It may happen in the initial days of starting the medicine or if the dose has been increased. If you do experience one or more side effects, their severity may lessen over time as your body adjusts to the medicine. Anyone taking a beta blocker should be aware of the common side effects in order to be able to identify them and seek help from a doctor or nurse if they become severe or persistent.

Common side effects include:

• Dizziness or lightheadedness when rising from a bed or chair

• Fatigue

• Cold hands and feet

• Swelling of hands and feet

• Headache

• Nightmares

• Difficulty sleeping

• Nausea

• Heartburn

• Diarrhea or constipation

• Gas

If a physician increases your dose, you might experience rapid weight gain. If you gain three or more pounds in one day, or if you continue to gain weight for more than two days you should consult your doctor.

Acute side effects that can also result from the drug include shortness of breath, wheezing, difficulty breathing, skin rash, severe vomiting, diarrhea, and changes in heartbeat.

Your doctor should know if you are taking any other medications, whether for high blood pressure or just over-the-counter pills. Combining beta blockers with other medications can have negative consequences.  For example, combined with a thiazide diuretic, a beta blocker increases long-term risk of diabetes. Other drugs, such as anti-depressants, allergy shots, insulin, and medicines for diabetes, asthma, and chronic bronchitis may increase the effect of beta blockers to an unhealthy level.

Once you have started taking a beta blocker, be prepared to take it for a long time.

You should not stop taking your beta-blocker medicine suddenly; this can trigger heart palpitations, chest pains, or a rise in blood pressure. If you must stop taking the drug or switch over to another medicine, your doctor should warn you about these risks and begin reducing your dose gradually.

If you operate heavy machinery or drive for a living, your doctor needs to know before you start taking beta blockers. Possible side effects such as dizziness can be dangerous to you. 

Anyone taking the drug should avoid alcohol, which can lower blood pressure even further and in some cases too much. Food and drinks containing caffeine, cough and cold medicines, antihistamines, and antacids containing aluminum should also be avoided. If you have to undergo a surgery that requires anesthesia, your physician might withhold the drug.

Know Your Medicine 

Once you begin a beta-blocker prescription, remain aware of the possible side effects and contact your doctor immediately if you notice any symptoms. Never stop taking beta blockers suddenly; this can lead to harmful consequences.  You'll get the maximum benefit from the medicine by remembering to take doses on time, with food, all the while avoiding alcohol and caffeine. Closely monitoring your blood sugar levels is advisable for diabetics. Always follow instructions on the drug label and the advice from your physician when using beta blockers.