Pathophysiology of Hypertension

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Sustained elevation of systolic, diastolic blood pressure or both

Types

Primary hypertension (85 to 95% cases) – unknown cause(Haemodynamic changes, environmental factors)

Secondary hypertension – identified cause (chronic kidney disease, primary aldosteronism)

Gestational hypertension – develops after 20 wk gestation

Prescription contains

Diuretics (Hydrochlorothiazide, Indapamide, Furosemide, Torsemide, Spironolactone)

Diuretics cause the kidneys to remove more sodium and water from the body, which helps to relax the blood vessel walls, thereby lowering blood pressure.

Thiazides:

Hydrochlorothiazide – 12.5–50 mg once/day

Indapamide – 1.25–5 mg once/day

Chlorthalidone – 12.5–50 mg once/day

Potassium sparing diuretics:

Spironolactone – 25–100mg once/day

Loop diuretics:

Furosemide – 20–320 mg twice/day

Torsemide – 5–100 mg once/day.

Angiotensin converting enzyme inhibitors (Ramipril,Enalapril,Captopril)

– Angiotensin converting enzyme inhibitors (ACE inhibitors) are drugs that block the body’s production of angiotensin II. Angiotensin II is a hormone that circulates in the blood and has many effects on the cardiovascular system; its main role is to constrict blood vessels. This constriction can cause high blood pressure and increase the work required for the heart to pump blood into the body’s main arteries. This causes a problem for the heart muscle if it has been weakened by a heart attack or heart failure. Blocking production of angiotensin II with ACE inhibitors prevents constriction of blood vessels, lowers blood pressure, and lessens the energy the heart has to expend from beat to beat.

Ramipril – 1.25–20 mg once/day

Enalapril – 2.5–40 mg once/day

Captopril – 12.5–150 mg twice/day

Lisinopril – 5–40 mg once/day

Perindopril – 4–8 mg once/day.

Calcium channel blockers (Amlodipine,Nifedipine,Verapamil,Diltiazem)

– Calcium channel blockers prevent calcium from entering cells of the heart and blood vessel walls, resulting in lower blood pressure. Calcium channel blockers, also called calcium antagonists, relax and widen blood vessels by affecting the muscle cells in the arterial walls.

Some calcium channel blockers have the added benefit of slowing your heart rate, which can further reduce blood pressure, relieve chest pain (angina) and control an irregular heartbeat.

Amlodipine – 2.5–10 mg once/day

Verapamil – 40–120 mg thrice/day, 120–480 mg once/day (sustained release)

Diltiazem – 60–180 mg twice/day (sustained), 120–360 mg once/day (extended)

Nifedipine – 30–90 mg once/day (extended).

β blockers (Metoprolol, Atenolol, Bisoprolol, Propranolol)

– Beta-blockers lower your blood pressure by blocking the effect of hormones called adrenaline and ­noradrenaline. By blocking these hormones, beta-blockers slow down your heart rate and reduce the force at which blood is pumped round your body.

Beta-blockers also block your kidneys from ­producing a hormone called angiotensin II. Reducing the amount of angiotensin in your body allows your blood vessels to relax and widen, making it easier for blood to flow through.

Metoprolol – 25–150 mg twice/day, 50– 400 mg once/day(extended)

Atenolol – 25–100 mg once/day

Bisoprolol – 2.5–20 mg once/day

Propranolol – 20–160 mg twice/day, 60–320 mg once/day (long acting)

Carvedilol – 6.25–25 mg twice/day, 20–80 mg once/day (controlled release).

Angiotensin receptor blockers (Telmisartan, Losartán, Olmesartán)

– Angiotensin II receptor blockers help relax your blood vessels, which lowers your blood pressure and makes it easier for your heart to pump blood.

Angiotensin II is a natural substance in your body that affects your cardiovascular system in many ways, such as by narrowing your blood vessels. This narrowing can increase your blood pressure and force your heart to work harder. Angiotensin II also starts the release of a hormone that increases the amount of sodium and water in your body, which can lead to increased blood pressure. Angiotensin II can also thicken and stiffen the walls of your blood vessels and heart.

Angiotensin II receptor blockers block the action of angiotensin II. That allows blood vessels to widen (dilate).

Telmisartan – 20–80 mg once/day

Losartan – 25–100 mg once/day

Olmesartan – 20–40 mg once/day

Valsartan – 80–320 mg once/day.

Centrally acting agents:

α2-Agonists (Methyldopa, Clonidine)

– Alpha-adrenergic receptors play an important role in the regulation of blood pressure (BP). There are 2 principal types of alpha receptors, alpha 1 and alpha 2, and both participate in circulatory control. Alpha 1 receptors are the classic postsynaptic alpha receptors and are found on vascular smooth muscle. They determine both arteriolar resistance and venous capacitance, and thus BP. Alpha 2 receptors are found both in the brain and in the periphery. In the brain stem, they modulate sympathetic outflow. Their function in the periphery is not yet fully understood, but they may contribute both to control of sympathetic tone and to local and regional blood flow. Drugs that enhance central alpha 2 activity, such as clonidine, guanfacine and the active metabolite of methyldopa, can significantly lower BP and are effective in the long-term control of hypertension, either alone or in combination with other drugs.

α-Blockers (Prazosin,Terazosin)

– Alpha blockers relax certain muscles and help small blood vessels remain open. They work by keeping the hormone norepinephrine (noradrenaline) from tightening the muscles in the walls of smaller arteries and veins. Blocking that effect causes the vessels to remain open and relaxed. This improves blood flow and lowers blood pressure.

Because alpha blockers also relax other muscles throughout the body, these medications can help improve urine flow in older men with prostate problems.

α2-Agonists:

Methyldopa – 250–1000 mg twice/day

Clonidine – 0.05–0.3 mg twice/day

α1-Blockers:

Prazosin – 1–10 mg twice/day

Terazosin – 1–20 mg once/day.

Vasodilators (Hydralazine)

– Vasodilation (or vasodilatation) refers to the widening of blood vessels.[1] It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. In essence, the process is the opposite of vasoconstriction, which is the narrowing of blood vessels.

When blood vessels dilate, the flow of blood is increased due to a decrease in vascular resistance. Therefore, dilation of arterial blood vessels (mainly the arterioles) decreases blood pressure. The response may be intrinsic (due to local processes in the surrounding tissue) or extrinsic (due to hormones or the nervous system). In addition, the response may be localized to a specific organ (depending on the metabolic needs of a particular tissue, as during strenuous exercise), or it may be systemic (seen throughout the entire systemic circulation).

Drugs that cause vasodilation are termed vasodilators. 

Hydralazine – 10–50 mg thrice/day

 

Classification

Condition

BP value

Normal

<120/80 mmHg

Prehypertension

120-139 / 80-89 mmHg

Stage 1

140-159 or 90-99 mmHg

Stage 2

≥160 mmHg or ≥100 mmHg

Counselling on side effects

Diuretics – depleted potassium levels- dietary intake of potassium through banana, (caution required in diabetics), coconut water, guava elevated triglycerides and uric acid monitor periodically especially in gouty persons increased photosensitivity use sunscreen

ACE inhibitors – persistent cough if intolerable consult doctor (prefer use of ARBs), elevated potassium levels, serum creatinine

CCBs – edema of legs (amlodipine)-regular walking every day, constipation – troublesome then go for extended release formulations,shortness of breath and dizziness(nifedipine immediate release formulation)

β blockers – bronchospasm  if severe report to physician, cardioselective agents preferred, masks insulin induced hypoglycaemia –  monitor blood glucose levels periodically, decreased exercise tolerance

ARBs – allergic reactions, decreased white blood cell count(rare)

Centrally acting agents – postural hypotension gradually change position (Eg: turn right side and get up slowly from bed), dizziness, vertigo so prefer at bedtime

Vasodilators – headache, increased heart rate

 

Controlling triggering factors in hypertension

  • Dietary salt intake
  • Alcohol consumption
  • Obesity
  • Use of NSAIDs, oral contraceptives.

Environmental factors for hypertension

  • Dietary Na, obesity, stress affects only genetically susceptible people at younger ages and in patients > 65 years, high salt intake precipitates hypertension, gestational hypertension.

Counselling on diet, exercise, lifestyle management

  • Reduce dietary salt intake to half teaspoon (2.4g/day)
  • Diet Rich in Potassium ,Calcium magnesium & fibre helps in lowering the elevated levels of Bp
  • adequate intake of B vitamins, which protect the nerve cells,
  • Vitamin C & E which can help in prevent vascular disease
  • Diet rich in fruits, vegetables and unsaturated fat (fish, nuts, olive oil)
  • Limit alcohol consumption to 30ml day
  • Regular exercise – 30min/day, 5 days/week
  • Weight loss to have BMI of 18.5- 24.5
  • Foods Rich In B Vitamin
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