Propranolol | A Beta-Adrenergic Receptor Antagonist

Introduction

Propranolol, available under the brand name of Inderal is a non-selective beta adrenergic antagonist is used to treat a variety of conditions, including hypertension, angina, atrial fibrillation, myocardial infarction, migraine, essential tremor, and hypertrophic subaortic stenosis.

Pharmacodynamics

Propranolol belongs to a beta-adrenergic receptor antagonist is used to treat hypertension. Given once or twice daily, depending on the indication, propranolol has a long duration of action. Patients who quit taking propranolol abruptly risk worsening of their angina and myocardial infarctions.
The S(-)-enantiomer of propranolol, a racemic combination of two enantiomers, has roughly 100 times the binding affinity for beta adrenergic receptors than the R(-)-enantiomer. 9 The most prevalent illness for which propranolol is prescribed is hypertension.

Mode of Action

Nonselective beta-adrenoreceptor antagonist Propranolol is also categorized as a class II antiarrhythmic. It responds by competitively blocking the heart’s normal epinephrine and norepinephrine-induced beta-1 and beta-2 adrenergic activation.

On cardiac myocytes, including the sinoatrial and atrioventricular nodes, there are beta-1 receptors. These receptors are activated, which results in an increase in cyclic AMP and an increase in intracellular calcium. Increased muscle fiber contractility results from this mechanism. Beta-adrenergic receptor blockade causes the heart’s overall workload to be reduced, which in turn lowers oxygen consumption and causes myocardial remodeling. [8]
On the other hand, beta-2 receptor activation results in an increase in cyclic AMP, which activates protein kinase A and causes smooth muscle cells in many organs and arteries to relax. Therefore, there is a slight vasoconstriction when beta-2 receptors are inhibited. Due to this action, it can be difficult for asthmatics to administer emergency epinephrine since it prevents epinephrine from potentially binding to pulmonary receptors. [9] Beta-blockers have a Vd of approximately 4 to 6 L/kg and are well distributed throughout the body. They are also highly protein-bound.

Indications

Hypertension can be treated with propranolol. Additionally, myocardial infarction, atrial fibrillation, migraine, essential tremor, hypertrophic subaortic stenosis, pheochromocytoma, and proliferating infantile hemangioma are all conditions for which propranolol is prescribed.

Availability & Usage

Beta-blockers are processed mostly in the liver, like the majority of drugs ( both the active and inactive compounds). Due to first-pass metabolism in the hepatic circulation, only around 25% of the medicine consumed enters the systemic circulation.

Propranolol’s active metabolite, 4-hydroxypropranolol, is created via hydroxylation with the help of the CYP2D6 enzyme.
Additionally, propranolol, like the majority of ingested drugs, is primarily eliminated by the kidneys, having a half-life of between 3 and 6 hours in people with healthy renal systems.

You can administer propranolol intravenously or orally. Continuous ECG monitoring should be done while a gradual infusion is administered intravenously. This method of administration is most frequently used in inpatient settings.

The dosage of propranolol varies, mainly depending on the ailment it is used to treat.

Side Effects

Bradycardia, gastrointestinal problems, abdominal pain, nausea, erectile dysfunction, and wheezing/bronchospasms are some of the most typical side effects of using propranolol. Use of propranolol may also result in weariness, drowsiness, and cold extremities. Hallucinations, insulin resistance, and allergic reactions are a few severe side effects to be aware of. Before writing a propranolol prescription for a patient, prescribers must go over all the side effects with them.

Drug Interation
(while taking with other medicine)

Abacavir	Propranolol may decrease the excretion rate of Abacavir which could result in a higher serum level.
Abametapir	The serum concentration of Propranolol can be increased when it is combined with Abametapir.
Abatacept	The metabolism of Propranolol can be increased when combined with Abatacept.
Abiraterone	The serum concentration of Propranolol can be increased when it is combined with Abiraterone.
Abrocitinib	The metabolism of Abrocitinib can be decreased when combined with Propranolol.
Acalabrutinib	The metabolism of Propranolol can be decreased when combined with Acalabrutinib.
Acarbose	The therapeutic efficacy of Acarbose can be increased when used in combination with Propranolol.
Acebutolol	Propranolol may increase the arrhythmogenic activities of Acebutolol.
Aceclofenac	Aceclofenac may decrease the antihypertensive activities of Propranolol.
Acemetacin	Acemetacin may decrease the antihypertensive activities of Propranolol.

Important Warning

In some cases, propranolol may result in heart failure. If you experience chest pain or discomfort, dilated neck veins, intense exhaustion, erratic breathing, an irregular heartbeat, swelling of the face, fingers, feet, or lower legs, or weight gain, consult your doctor immediately once.

Available Brands

Inderal