Antihypertensive

Antihypertensive

• 

  Hydrochlorothiazide

• 

  Captopril

• 

  Valsartan

• 

  Propranolol

Antihypertensive

Antihypertensives are a class of drugs that are used to treat hypertension (high blood pressure). Hypertension is a common condition that can lead to serious complications such as stroke, heart attack, and kidney failure. Antihypertensive medications work by various mechanisms to lower blood pressure and reduce the risk of these complications.

Classes of Antihypertensive Drugs

There are several classes of antihypertensive drugs, each working through different mechanisms:

Diuretics

Diuretics help the kidneys remove excess salt and water from the body, which decreases blood volume and lowers blood pressure. Common diuretics include thiazide diuretics, loop diuretics, and potassium-sparing diuretics.

Beta Blockers

Beta blockers reduce blood pressure by blocking the effects of epinephrine (adrenaline) and slowing the heart rate. They are often used in patients with angina or heart failure.

ACE Inhibitors

Angiotensin-converting enzyme inhibitors (ACE inhibitors) prevent the formation of angiotensin II, a substance that narrows blood vessels. This helps to relax blood vessels and lower blood pressure.

Angiotensin II Receptor Blockers

Angiotensin II receptor blockers (ARBs) block the action of angiotensin II, allowing blood vessels to remain open. They are often used as an alternative to ACE inhibitors.

Calcium Channel Blockers

Calcium channel blockers prevent calcium from entering the cells of the heart and blood vessel walls, leading to relaxed blood vessels and lower blood pressure.

Alpha Blockers

Alpha blockers reduce nerve impulses that tighten blood vessels, allowing blood to flow more freely.

Central Agonists

Central agonists decrease blood pressure by preventing the brain from sending signals to the nervous system to increase heart rate and narrow blood vessels.

Vasodilators

Vasodilators directly relax the muscles in the blood vessel walls, causing the vessels to widen and lower blood pressure.

Mechanism of Action

Antihypertensive drugs work through various mechanisms to lower blood pressure:

• Volume Reduction: Diuretics reduce blood volume by increasing urine output.
• Heart Rate Reduction: Beta blockers slow the heart rate and reduce cardiac output.
• Vasodilation: ACE inhibitors, ARBs, calcium channel blockers, and vasodilators relax blood vessels.
• Sympathetic Nervous System Inhibition: Alpha blockers and central agonists reduce nerve signals that increase blood pressure.

Side Effects

Antihypertensive medications can have side effects, which vary depending on the class of drug. Common side effects include:

• Diuretics: Electrolyte imbalance, dehydration.
• Beta Blockers: Fatigue, cold extremities, bradycardia.
• ACE Inhibitors: Cough, elevated blood potassium levels.
• ARBs: Dizziness, headache.
• Calcium Channel Blockers: Swelling, constipation.
• Alpha Blockers: Dizziness, headache.
• Central Agonists: Drowsiness, dry mouth.
• Vasodilators: Headache, flushing.

Related Pages

• Hypertension
• Cardiovascular disease
• Renin-angiotensin system
• Blood pressure

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I

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K

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