🔅 BETA BLOCKERS

– Beta blockers are a class of medicines that lower blood pressure and widen veins and arteries. They also may treat or prevent irregular heart rhythms, heart failure, chest pain, heart attacks and migraine.

– They work by blocking the effects of the hormone epinephrine, also known as adrenaline, on beta receptors in the heart and blood vessels. There are different types of beta blockers, depending on their selectivity and specificity for beta receptors. Beta receptors come in three subtypes namely:

• Beta-1

• Beta-2

• Beta-3

– Beta-1 receptors are mainly found in the heart and kidneys, beta-2 receptors are mainly found in the lungs and smooth muscles, and beta-3 receptors are mainly found in fat cells.

– Some beta blockers are non-selective, meaning they block both beta-1 and beta-2 receptors. These include: nadolol, penbutolol, pindolol, propranolol, sotalol, and timolol. Non-selective beta blockers may have more side effects, especially in people with asthma or diabetes.

Some beta blockers are cardioselective, meaning they mainly block beta-1 receptors and have less effect on beta-2 receptors. These include: acebutolol, atenolol, betaxolol, bisoprolol, esmolol, and metoprolol. Cardioselective beta blockers may be safer for people with asthma or diabetes, but they still need to be used with caution. Some beta blockers are vasodilatory, meaning they also relax the blood vessels by blocking alpha receptors or stimulating nitric oxide production. These include: carvedilol, labetalol, and nebivolol. Vasodilatory beta blockers may have additional benefits for people with heart failure or high blood pressure.

– Beta blockers are used for various conditions, such as:

🔅 High blood pressure: Beta blockers can lower blood pressure by reducing the heart rate and the force of contraction. They are usually used in combination with other medicines, such as diuretics, calcium channel blockers, or angiotensin-converting enzyme inhibitors.

🔅 Angina: Beta blockers can relieve chest pain by decreasing the oxygen demand of the heart. They can also prevent angina attacks by reducing the frequency and severity of abnormal heart rhythms.

🔅 Heart failure: Beta blockers can improve the survival and symptoms of people with heart failure by slowing the progression of the disease and reducing the risk of hospitalization. They can also prevent or treat arrhythmias that may worsen heart failure.

🔅 Arrhythmias: Beta blockers can prevent or treat abnormal heart rhythms by stabilizing the electrical activity of the heart. They can also reduce the risk of stroke and sudden cardiac death in people with atrial fibrillation or ventricular tachycardia.

🔅 Heart attack: Beta blockers can reduce the damage to the heart muscle and improve the outcome of people who have had a heart attack. They can also prevent further heart attacks by lowering blood pressure and preventing arrhythmias.

🔅 Migraine: Beta blockers can prevent migraine headaches by reducing the dilation and inflammation of the blood vessels in the brain. They can also reduce the frequency and severity of migraine attacks.

🔅 Other conditions: Beta blockers can also be used for other conditions, such as glaucoma, essential tremor, anxiety, hyperthyroidism, and pheochromocytoma.

– Beta blockers are generally safe and effective, but they may have some side effects and risks. These include cold hands or feet, fatigue, weight gain, dizziness, insomnia, depression, and sexual dysfunction. These side effects are usually mild and may improve over time or with dose adjustment.

The difference between selective and non-selective beta blockers

– The difference between selective and non-selective beta blockers lies in their specificity of action. Selective beta blockers mainly block beta-1 receptors, which are mostly found in the heart and kidneys. Non-selective beta blockers block both beta-1 and beta-2 receptors, which are also found in the lungs and smooth muscles.

This means that selective beta blockers may have a more targeted effect on the heart and blood vessels, while non-selective beta blockers may have a wider range of effects on the body. For example, non-selective beta blockers may worsen asthma symptoms by constricting the airways, or affect blood sugar levels by inhibiting the release of insulin. Therefore, selective beta blockers may be safer for people with asthma or diabetes, but they still need to be used with caution and under medical supervision. Non-selective beta blockers should be avoided or used at low doses for these people.

Some examples of selective beta blockers are atenolol, metoprolol, nebivolol, and bisoprolol. Some examples of non-selective beta blockers are nadolol, pindolol, propranolol, and timolol.

▶️ Can I take beta blockers if I have asthma or diabetes?

If you have asthma or diabetes, you may need to be careful about taking beta blockers, as they may have some risks and side effects for you, such as: headaches, diabetes, asthma and Raynaud phenomenon.

▶️ Risks of taking Beta Blockers

– Some of the risks of taking beta blockers are:

• Headache

– This is the most common side effect, occurring in up to 25% of people who undergo a spinal tap. It is caused by fluid leaking from the puncture site, resulting in low pressure in the cerebrospinal fluid. The headache typically worsens when sitting or standing, and improves when lying down. It may also be accompanied by nausea, vomiting, and dizziness. It usually resolves within a week with rest, hydration, and painkillers.

• Diabetes

– Beta blockers may affect blood sugar levels and mask the symptoms of low blood sugar, such as rapid heartbeat, sweating, and tremor. People with diabetes who take beta blockers need to monitor their blood sugar regularly and adjust their medication or diet accordingly.

• Asthma

– Beta blockers may worsen asthma symptoms by constricting the airways and inhibiting the bronchodilator effect of epinephrine. People with asthma who take beta blockers need to use them with caution and under medical supervision. Non-selective beta blockers, which block both beta-1 and beta-2 receptors, should be avoided, and cardioselective beta blockers, which mainly block beta-1 receptors, should be used at low doses.

• Raynaud phenomenon

– Beta blockers may aggravate Raynaud's phenomenon, a condition that causes the fingers and toes to become cold, numb, and discolored when exposed to cold or stress. This is due to the reduced blood flow to the extremities caused by beta blockers. People with Raynaud's phenomenon who take beta blockers need to keep their hands and feet warm and avoid triggers.

• Rebound hypertension

– Beta blockers should not be stopped suddenly, as this may cause a sudden increase in blood pressure and heart rate. This can lead to chest pain, heart attack, or stroke. Beta blockers should be tapered off gradually under medical guidance.

– These are some of the possible risks of taking beta blockers. However, beta blockers are generally safe and effective, and the benefits usually outweigh the potential harms. You should always consult your doctor before taking any beta blockers, and follow their instructions and advice. You should also report any side effects or concerns to your doctor as soon as possible.1