Beta Blockers List

Beta blockers are important drugs that are used to treat a variety of diseases. These drugs are called beta blockers because they inhibit adrenergic responses mediated through the beta receptors. There are three beta receptors in the body, namely β₁, β₂ and β₃. All beta blockers are competitive antagonists in nature. Some of these drugs are selective in nature, that is, they do not act on all three beta receptors. These drugs are commonly used for treating various illnesses including high blood pressure, migraine, angina, cardiac arrhythmias, myocardial infarctions and pheochromocytoma. Due to their various uses, it is imperative that we know details of these highly useful drugs. Given below is an exhaustive list of beta blockers:

Non Selective Beta Blockers List

• Propranolol
• Sotalol
• Timolol
• Pindolol
• Levobunolol
• Nadolol
• Metipranolol

Cardioselective Beta Blockers List

• Atenolol
• Acebutolol
• Metoprolol
• Bisoprolol
• Esmolol
• Betaxolol
• Nebivolol

Alpha and Beta Blockers List

• Labetalol
• Carvedilol

Propranolol

Propranolol is considered the prototype in beta blockers, and it figures prominently in every beta blockers list. Propranolol was introduced in 1963, and was considered a huge breakthrough drug. It is a non-selective beta blocker. Although it competitively blocks both β₁ and β₂, it has weak activity on β₃ receptors. Along with being non-selective in nature, it also exhibits membrane stabilizing activity.

Effects of Propranolol:
Being a non-selective beta blocker, propranolol acts on all the β receptors in the body, thus bringing about the following effects:

• Heart: Propranolol decreases the heart rate, force of contraction and the cardiac output. It prolongs the systolic phase by retarding conduction in the myocardium.
• Respiratory tract: Propranolol increases the bronchial resistance by blocking β₂ receptors. This effect is hardly discernible in normal individuals as the sympathetic bronchodilator tone is minimal.
• Central Nervous System: Propranolol suppresses anxiety in short term stressful situations, although this is brought about more due to its peripheral activity rather than its central activity.
• Local anesthetic: Propranolol can act as a potent anesthetic when used as lidocaine, but it is not used because of its irritant property.
• Metabolic effects: Though propranolol does not have an effect on the blood sugar level, prolonged use may reduce carbohydrate tolerance by decreasing release of insulin.
• Skeletal muscle: Propranolol decreases adrenergically provoked tremors. This is a peripheral action that is exerted directly on the muscles.
• Eye: Propranolol, along with certain other β blockers, reduces secretion of aqueous humor, thus, lowering the intra-ocular tension.

Indications:
Due to the multiple beta blocker effects that propranolol has on the sympathetic system, this prototype drug is used to treat several heart diseases.

• Hypertension: Propranolol is a commonly used hypertension medication, although it has a relatively mild antihypertensive activity. This is because it has good patient acceptability.
• Angina pectoris: Angina pectoris is a condition where, due to transient hypoxia of the heart muscle, a person experiences severe chest pain. This hypoxic condition occurs due to narrowing of the coronary arteries. Propranolol is used in treating angina, as it decreases the workload of the heart. If taken on a regular basis, it decreases the frequency of attacks.
• Myocardial infarction: Propranolol is also given to patients that have suffered from a myocardial infarction, that is, a heart attack. They are used as a secondary prophylaxis of myocardial infarction, as they prevent re-infarction and sudden ventricular fibrillation at the second attack.
• Stress and Anxiety: One of the oft used beta blockers for anxiety, propranolol blocks the sympathetic nerves, thus, inhibiting the peripheral manifestations of stress and anxiety.
• Tremors: Being a non-selective β blocker, propranolol helps in treating essential involuntary rhythmic tremors. However, it does not help in treating parkinsonian tremor.
• Pheochromocytoma: β blockers like propranolol maybe used to control tachycardia and arrhythmia but should only be used after an α blocker has been administered, or else the blood pressure could dangerously shoot up.
• Migraine: Propranolol is the most effective drug for chronic prophylaxis of migraine, as it reduces the frequency and severity of the attacks in almost 70% of the patients. The effect is seen in four weeks and is sustained during prolonged therapy.
• Thyrotoxicosis: Propranolol rapidly controls symptoms associated with hyperthyroidism, like palpitations, sweating, tremors etc.) without significantly altering the thyroid status. It is especially used post-operatively while awaiting response to antithyroid drugs or radioactive iodine.
• Cardiac Arrythmias: β blockers like propranolol suppress extrasystoles and tachycardias, especially those that are mediated adrenergically. Propranolol helps control ventricular rate in atrial fibrillation and flutter, but only occasionally restores sinus rhythm.

Contraindications:
Some of the effects produced by propranolol maybe harmful for people suffering from specific diseases. These include:

• Congestive Cardiac Failure: Due to its action of blockage of the sympathetic support to the heart, it can precipitate edema and thus, congestive heart failure, especially during cardiovascular stress.
• Asthma: Propranolol is contracindicated in cases of asthma because it increases bronchial resistance by blocking β₂ receptors, which consistently worsens asthma and, which may even precipitate a severe asthma attack. It also worsens chronic obstructive lung disease.
• Heart block: In cases of complete or partial heart block, propranolol is strictly contraindicated as it may lead to a cardiac arrest.
• Corornary artery disease: As propranolol has the effect of altering lipid profiles, by causing an increase in the LDL-cholesterol and a decrease in the HDL-cholesterol. This precipitates the condition of coronary heart disease

Side effects:
Most beta blockers side effects are mild as these drugs are quite well tolerated. However, here are a few propranolol side effects:

• It accentuates myocardial insufficiency.
• It may bring about bradycaria (decreased heart rate).
• It worsens chronic obstructive lung disease
• It may impair carbohydrate tolerance in borderline diabetics
• It alters the plasma lipid profile on prolonged use
• It may lead to cold hands and feet and worsening of peripheral vascular disease
• It may lead to lethargy, excessive fatigue and decreased capacity for exercise.

Sotalol

Sotalol is a drug that figures in non-selective beta blockers list. It does not show any intrinsic sympathomimetic activity and does not block alpha receptors. Sotalol is a one of the most unique beta blockers drugs as it not only shows activity on beta receptors, but it also blocks potassium channels in the heart. Thus, it is used to treat atrial fibrillation and other life threatening ventricular arrhythmias, as it helps return the heartbeat to a normal rhythm and considerably reduces risk factors. This drug is normally avoided in children and pregnant women, as there is not enough data to prove their safety in such individuals. Sotalol is strictly contraindicated in nursing mothers, as it can pass through into breast milk in significant amounts, thus posing a risk to the infant. Sotalol is also contraindicated in patients with kidney diseases.

There are certain risks associated with sotalol. This drug should be used only if absolutely necessary, in arrhythmia cases. ECG monitoring is required for three days after a steady sotalol dosage has been reached, as this medicine can initially cause irregular heartbeats. Sotalol is contraindicated in diseases which disturb the electrolyte balance of the body, like diarrhea, as low electrolyte levels may increase the risk of dangerous arrhythmias. Furthermore, sotalol interacts with many drugs including calcium channel blockers, antacids and certain diuretics, among others. An overdose of sotalol can lead to dangerously low blood pressure.

As with most beta blockers side effects, sotalol may cause drowsiness, dizziness and feeling of being light headed.

Timolol

A drug that is a part of the first generation non-selective beta blockers list, timolol is also used to treat hypertension, angina, heart attacks, migraine and headaches. Like propranolol, it decreases the heart rate, thus, decreasing the systolic and diastolic pressure. It is relatively well tolerated, with very mild side effects like nausea and cold hands and feet. It is to be used only if necessary, in pregnant ladies or nursing mothers. Timolol is occasionally {implicated} as one of the beta blockers for anxiety.
A special use of timolol includes its use in glaucoma and other eye conditions. It reduces the pressure in the eyes when used as eye drops on a regular basis. The medication may initially lead to a slight stinging or burning sensation, but this normally subsides after regular use. If this stinging persists, or if pain develops, then discontinue use of the medication and consult an ophthalmologist immediately.

Timolol interacts with drugs such as calcium channel blockers and clonidine.

Pindolol

One of the few beta blocker drugs that exhibits prominent intrinsic sympathomimetic activity, pindolol is primarily used as an anti-hypertensive. It is especially given to patients who develop marked bradycardia on prolonged use of propranolol. Another advantage of this drug is that, rebound hypertension symptoms on withdrawal are less. Additionally, the effective dose range is quite narrow.

This drug has relatively few side effects and is quite well tolerated. However, it is contraindicated in kidney disease patients and it can show severe withdrawal symptoms if abruptly stopped. Ironically, while beta blockers are mostly used in cases of heart failure, pindolol and certain other beta blocker drugs can worsen heart failure in some instances. Prolonged use of pindolol and other non-selective beta blockers can lead to masking of symptoms of hypoglycemia (low blood sugar level). This can be quite problematic in diabetics. This drug is contraindicated in nursing mothers.

Atenolol

Atenolol prominently figures on the cardioselective beta blockers list. It is a β₁ blocker that has low lipid solubility. It is incompletely absorbed orally. However, due to its longer duration of action, once daily dose is often sufficient. Lesser side effects are seen when related to the central nervous system. Also, the lipid profiles aren't significantly altered, thus, it is not dangerous to use even in people with coronary artery disease. However, in patients suffering from coronary artery disease, abruptly stopping administration of atenolol can worsen angina symptoms, which may even precipitate heart attacks. Also, atenolol is one of the most commonly used drugs for hypertension, as it brings about lowering of high blood pressure and angina. Atenolol is also helpful in treating tachycardias (very fast heart rate), in myocardial infarctions, migraine and tremors.

Atenolol comes in tablet form, and can be taken either before meals or at night. However, this drug should not be prescribed with calcium channel blockers, as synergistically, they can drastically bring down the blood pressure and the heart rate to dangerous levels.

Atenolol is contraindicated in pregnancy as it may harm the fetus and cause growth retardation. The side effects of atenolol are similar to most beta blockers side effects.

Acebutolol

This is also a cardioselective beta blocker with marked partial agnostic and membrane stabilizing properties. It has a relatively lesser effect on the heart rate. The side effects seen are similar to those seen in metoprolol. Due to its long half-life, a single dose of acebutolol suffices for most patients.

Due to its cardioselective activity, it is the preferred beta blocker in asthmatics and chronic obstructive pulmonary disease (COPD) patients. Acebutolol is available in capsule form, and is normally taken with a meal or can also be taken on an empty stomach. Acebutolol is used alone or in combination with other drugs to treat hypertension and arrhythmias. It is also used to treat angina pectoris. Side effects of this drug include fatigue, dizziness and headaches.

Metoprolol

Metoprolol is considered as the prototype in cardioselective beta blockers list. It acts on the β₁ receptors. Its potency to block cardiac stimulation is similar to propranolol. Although it is relatively less likely to worsen asthma, it is still not safe for asthmatics. It is also the preferred beta blocker drug in people suffering from diabetes. Also, patients complaining of cold hands and feet while on propranolol often respond well to metoprolol. The side effects of metaprolol are mild. It is generally given orally, though in severe cases of myocardial infarction it can also be given intravenously.
It is also available in an extended release version. Metoprolol should be taken either with a meal, or immediately after a meal.

It reverses the effects of stress hormones, thus it is one of the recommended beta blockers for anxiety treatment. However, it can significantly precipitate asthma.
It is not used in children, and like most beta blockers, is contraindicated in nursing mothers.

Bisoprolol

Another one of beta blockers drugs, that is strictly cardioselective in action. It lacks intrinsic sympathomimetic activity and is thus, suitable for daily administration in patients suffering from hypertension and angina. The mechanism of action and side effects of this drug are similar to those seen in acebutolol. It is available in tablet form and is to be taken once a day, with a meal or on an empty stomach. Incidentally, this is one of the only beta blockers that is used in the treatment of congestive heart failure. The dose will depend on the severity of the hypertension and on how well the patient responds to this drug. The potency of this drug can be hampered if it is given in combination with NSAID's (non-steroidal anti-inflammatory drugs) such as ibuprofen.

Esmolol

A part of the cardioselective beta blockers list, it is an ultra-short acting β₁ blocker devoid of partial agnostic or membrane stabilizing activity. The plasma half life is less than ten minutes, as it is inactivated by esterates in the blood. Its action lasts for fifteen to twenty minutes, after termination of intravenous infusion. Thus, it has a rapid onset of action, with a short lasting but almost instantaneous fall in blood pressure. It has been used to terminate supraventricular tachycardia, arrhythmia during anesthesia, episodic atrial fibrillation thus, to reduce heart rate and blood pressure during and after a cardiac surgery, and in early treatment of myocardial infarction. Thus, it is used only for temporary treatment. Also, since the medication is given in intravenous mode, care has to be taken to ensure that there is no leakage of the drug into the veins, as this maybe injurious to health. As is common to most beta blockers side effects, esmolol may cause low blood pressure, nausea and dizziness.

Labetalol

Labetolol hyrdrochloride, along with carvedilol, is one of the two beta blockers drugs which act on both, alpha and beta receptors. This is possible because there are four stereoisomers of labetolol, each of which has a distinct profile of action on subtypes of α and β receptors. However, labetolol is five times more capable of blocking β than α receptors. The effects seen resemble those of low dose propranolol. The fall in blood pressure (both systolic and diastolic) occurs due to α₁ and β₁ blockade as well as β₂ agonism (vasodilation). High doses though, reduce cardiac output. One of the ways in which it differs from propranolol is that, limb blood flow increases with labetolol. Some major indications of labetolol include pheochromocytoma, clonidine withdrawal and essential hypertension. One major side effect of labetolol, however, is that it causes postural hypotension.
It is used for controlling high blood pressure, although it is not a cure for it.

Carvedilol

Carvedilol is one of the beta blockers drugs that has an action on β₁, β₂ and α₁ adrenoreceptors. It brings about vasodilation due to α₁ blockade. It also has an antioxidant property. It's mainly used in hypertension, and is the β blocker especially employed as a cardioprotective in congestive heart failure. It has a half life of two - eight hours. Carvedilol comes in tablet form and is to be taken twice a day, preferably with food. It should be taken at the same time everyday, to maintain an even level in the blood. Also, the drug should not be abruptly withdrawn, as it can lead to beta blockers side effects, which may lead to dire consequences.

This was an exhaustive beta blockers list. The discovery of these drugs is truly a landmark in pharmacology, as they are used for treating various ailments. So take full advantage of these drugs, as they are considered to be miracle drugs for hypertensives and other heart patients.