Side Effects of Beta Blockers

Beta blockers are medicines that reduce your blood pressure. They temporarily stop or reduce the body’s natural ‘fight-or-flight’ responses

Beta Blockers side effect

What are beta blockers?

Beta blockers are also called beta-adrenergic blocking agents, beta antagonists, and beta-adrenergic antagonists. These are medicines that reduce blood pressure. They temporarily stop or reduce the body’s natural ‘fight-or-flight’ responses. Beta blockers block the effects of adrenaline. Taking beta blockers make your heart beats more slowly. Since the heart uses less force, the blood pressure is reduced. Beta blockers also help by opening up the blood vessels to improve blood flow.

They reduce stress on the heart and the blood vessels in the brain. Beta-blockers helps to lower blood pressure, making them very beneficial for people who suffer from high blood pressure. They also protect against heart attacks. These medicines have also improved the outlook for people with heart failure.

They are used to treat or prevent different conditions such as high blood pressure, irregular heartbeat, angina, heart attack, congestive heart failure, heart rhythms, abnormal heart rhythms, anxiety, migraine, glaucoma, and overactive thyroid symptoms.

Propanolol, the first receptor-blocking drug, was developed by pharmacologist James Black in 1964. This development in medicine won him a Nobel Prize in Physiology and Medicine in 1988. This drug is still being used today.

How do Beta Blockers Work?

Beta blockers block the hormones adrenaline and noradrenaline in the sympathetic nervous system, a part of the autonomic nervous system. The sympathetic nervous system activates the ‘fight-or-flight’ response.

Adrenaline and noradrenaline are hormones that prepare the muscles in the body for exertion. This is vital when responding to danger. However, too much of these hormones can be dangerous. Excessive adrenaline can result in high blood pressure, rapid heartbeat, excessive sweating, anxiety, and palpitations.

To block these hormones, beta-blockers reduce oxygen demands and lowers pressure on the heart. As a result, there are fewer contractions in the muscles of the heart as it uses less force.

Beta blockers also hinder the production of angiotensin II, a hormone produced by the kidneys that can increase blood pressure by constricting the blood vessels. Reducing the production of angiotensin II results in improved blood flow as this relaxes and widens the blood vessels in the heart, the brain, and the rest of the body.

Uses of Beta Blockers

Beta blockers are commonly used with for high blood pressure, irregular heartbeat, angina, heart attack, congestive heart failure, heart rhythms, and abnormal heart rhythms.

Though less common, they may also be used for glaucoma, overactive thyroid, migraines, tremors, and anxiety.

  • Glaucoma. Using beta-blocker eye drops, high pressure within the eyeball is reduced. Beta-blockers reduce the production of fluid inside the eyeball.
  • Overactive thyroid and tremor. An overactive thyroid can cause rapid or irregular heartbeat and tremors. Beta blockers can slow down the heart rate of those affected by this condition. It can also reduce tremors usually experienced in the hands and fingers.
  • Migraine. Migraine is thought to be caused by changes in the blood vessels in the brain. Beta-blockers relax and open up blood flow in the blood vessels. However, it is not quite clear exactly how beta blockers prevent migraine symptoms. A 2012 study in the Journal of Headache and Pain suggested that it may be because beta blockers alter the excitability of the visual cortex in the brain.
  • Anxiety. Beta blockers block the effects of stress hormones called norepinephrine or noradrenaline. As a result, physical symptoms such as rapid heart rate, trembling, and sweating is reduced.

Beta Blockers Side Effect

The most common side effects of beta blockers are:

  • Nausea
  • Weakness
  • Dizziness
  • Fatigue
  • Headache
  • Weight gain
  • Slow heartbeat
  • Cold hands and feet
  • Swelling of the hands and feet
  • Dry mouth, skin, and eyes

The less common side effects of beta blockers are:

  • Abdominal cramps
  • Constipation
  • Diarrhea
  • Shortness of breath
  • Loss of sex drive
  • Slow heartbeat
  • Skin rash
  • Sore throat
  • Wheezing or trouble in breathing
  • Sleeping difficulties and disturbances


If you have a history of any of the following conditions, please advise your doctor before taking beta blockers.

  • Bronchospasm
  • Asthma
  • Diabetes
  • Slow heart rate
  • Uncontrolled heart failure
  • Severe peripheral arterial disease

Likewise, inform your doctor about all the medicines you’re taking, especially:

  • Other medications for high blood pressure
  • Antidepressants
  • Drugs for diabetes (including insulin)
  • Medications for asthma, chronic bronchitis, emphysema, or chronic obstructive pulmonary disease
  • Allergy shots
  • Antacids that contain aluminum
  • Over-the-counter (OTC) cough, cold, or allergy medicines

Beta blockers may trigger a severe asthma attack that is why they are generally not used on people with asthma.

For people who have diabetes, it is important to monitor your blood sugar regularly, because beta blockers can mask signs of low blood sugar, such as rapid heartbeat.

Beta blockers might raise your triglyceride levels and decrease your “good” high-density lipoprotein (HDL) cholesterol. However, this is often temporary. Do not abruptly stop taking beta blockers. Wait for your doctor to say so. Doing otherwise could result in a higher risk of heart attack or other heart problems.

Beta-blockers can also be used by pregnant women if recommended by their doctor.


There are also some food and drinks that you should avoid eating and drinking while taking beta blockers because they can have negative effects on your health.

  • Alcohol. The depressant effects of alcohol can lower blood pressure too much. It can also make your heart pound, something not ideal if you have rapid heartbeat problems.
  • Fatty Foods. Fatty foods increase the workload of the heart. Avoid foods that are deep-fried, and high in cholesterol and saturated fats. Fat is still necessary to your diet. Just choose fats that will not contribute to heart disease.
  • High Sodium Foods. Foods that are high in sodium also puts extra work on the heart. If you are suffering from high blood pressure, eating high sodium foods and taking beta blockers at the same time will be a bad idea. Salt contributes to high blood pressure. It will only negate the purpose of beta blockers.
  • High Potassium Foods. Avoid these foods because beta blockers can limit the uptake of potassium from the bloodstream. Some high potassium foods include papaya, oranges, pears, bananas, prunes, and raisins. Beta-blockers sometimes function differently, so it is best that you ask your doctor if you can eat high potassium foods. If the answer is yes, ask in what portion size.

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