20/05/2023
Propranolol Pharmacological action:
Propranolol is a beta-adrenergic receptor antagonist, also known as a beta-blocker. It blocks the action of adrenaline on beta-receptors in the heart and blood vessels. This causes a decrease in heart rate, blood pressure, and the workload of the heart. Propranolol also reduces the release of renin in the kidneys, which lowers blood pressure.
Uses:
Propranolol is primarily used to treat high blood pressure, angina, and certain heart rhythm disorders. It may also be used to prevent migraines and to treat essential tremor, anxiety, and stage fright.
Mode of action:
Propranolol blocks the action of adrenaline on beta-receptors in the heart and blood vessels. This causes a decrease in heart rate and the workload of the heart, as well as a decrease in blood pressure.
Site of action:
Propranolol acts on beta-adrenergic receptors in the heart and blood vessels, as well as on renin-secreting cells in the kidneys.
Side effects:
Side effects of propranolol can include fatigue, dizziness, headache, nausea, diarrhea, stomach pain, and sexual dysfunction. It can also cause slow heart rate, low blood pressure, and significant breathing difficulties in patients with asthma or chronic obstructive pulmonary disease (COPD). Rarely, it can cause severe allergic reactions, including anaphylaxis.
Contraindications:
Propranolol is contraindicated in patients with a history of severe allergic reactions to it or other beta-blockers, heart block, heart failure, or shock. It should also be avoided in patients with asthma or COPD, as well as in those with severe bradycardia (slow heart rate) or hypotension (low blood pressure).
Off-label uses:
Off-label uses of propranolol include the treatment of post-traumatic stress disorder (PTSD), alcohol withdrawal symptoms, and infantile hemangiomas (blood vessel tumors).
https://t.me/ALGrawany36/1832 Follow Me 4, [May 19, 2023 at 19:05]
Propranolol is a nonselective beta-blocker and it reduces the release of renin from the kidneys. Renin is an enzyme produced mainly by the juxtaglomerular cells in the kidneys. Renin plays a key role in the renin-angiotensin-aldosterone system (RAAS) which regulates blood volume, blood pressure, and electrolyte balance in the body.
The release of renin from the kidneys is triggered by a drop in blood pressure or a decrease in sodium levels in the blood. When the kidney detects low blood pressure or low sodium levels, it releases renin into the bloodstream. Renin then converts angiotensinogen, a protein produced by the liver, to angiotensin I.
Angiotensin I is then converted to angiotensin II by the angiotensin-converting enzyme (ACE), which is mainly found in the lungs. Angiotensin II is a potent vasoconstrictor, which means it narrows the blood vessels and increases blood pressure. Angiotensin II also stimulates the release of aldosterone from the adrenal glands, which promotes the reabsorption of sodium and water in the kidneys, and leads to an increase in blood volume and blood pressure.
Propranolol blocks the action of adrenaline and noradrenaline, which are hormones that act on beta-receptors in the juxtaglomerular cells of the kidneys. The activation of beta-receptors by these hormones stimulates the release of renin from the kidneys.
By blocking the action of these hormones, propranolol reduces the release of renin from the kidneys, and therefore reduces the activation of the RAAS. This leads to a reduction in blood pressure and a decrease in blood volume.
In summary, propranolol reduces the release of renin from the kidneys by blocking the action of adrenaline and noradrenaline on beta-receptors in the juxtaglomerular cells. This leads to a decrease in the activation of the RAAS, and a reduction in blood pressure and blood volume.
https://t.me/ALGrawany36/1834 Follow Me 4, [May 19, 2023 at 21:15]
Metoprolol, Carvedilol, and Bisoprolol are beta-blockers that act by blocking the action of adrenaline and noradrenaline on beta-adrenergic receptors in the heart, lungs, and blood vessels. All three drugs have similar mode of action and effectiveness.
Metoprolol selectively blocks beta-1 receptors in the heart, which reduces heart rate and cardiac output, leading to a reduction in blood pressure. It is used to treat hypertension, angina, heart failure, and to prevent heart attacks. The usual dose of metoprolol is between 50-200 mg per day.
Carvedilol is a non-selective beta-blocker that also has alpha-1 blocking activity. In addition to its beta-blocking effects, carvedilol also dilates blood vessels through alpha-1 blockade. This leads to a decrease in blood pressure and a reduction in heart rate, making it an effective medication for treating hypertension, heart failure, and angina. The usual dose of carvedilol is between 12.5-50 mg per day.
Bisoprolol is a highly selective beta-1 blocker that reduces heart rate and cardiac output, leading to a decrease in blood pressure. It is primarily used to treat hypertension and heart failure. The usual dose of bisoprolol is between 2.5-10 mg per day.
All three drugs have similar side effects, including fatigue, dizziness, headache, nausea, and stomach upset. However, carvedilol may also cause low blood pressure, severe hypotension, and fatigue. Moreover, Beta-blockers can worsen bronchospasm in patients with asthma, or chronic obstructive pulmonary disease (COPD), so they must be used with caution in such patients.
The choice of which beta-blocker to use depends on the patient's medical conditions and other factors, such as kidney function, age, and medication interactions. It is best to discuss with the doctor which medication is best for you.
