Heart attack and stroke are the main causes of death worldwide, and are associated with hypertension. Hypertension (High Blood Pressure) is sustained elevated resting blood pressure with systolic BP ≥ 130 mm Hg, diastolic BP ≥ 80 mm, or both. Hypertension with no known cause is most common. Hypertension with identified cause is usually due to kidney disease, primary aldosteronism, tumour growth, and sleep apnea. Prolonged hypertension damages target organs (cardiovascular system, eyes, brain, and kidneys), increasing risk of heart disease, heart attack, stroke, blindness, kidney failure, and early death.
Treatment includes lifestyle changes and drugs such as Beta Blockers, Diuretics, ACE Inhibitors, Angiotensin II Receptor Blockers, Calcium Channel Blockers, and Renin Inhibitors. All drugs come with side effects and contraindications, not excluding irreversible liver and kidney damage.
zoom in or view in landscape mode
Beta-blockers reduce blood pressure by reducing the heart rate and reducing the contraction force of the heart. This in turn reduces the amount of blood volume ejected out from the heart therefore reduces blood pressure. Generally, all Beta-blockers are similar in antihypertensive efficacy. Beta-blockers are contraindicated in patients with asthma, 2nd or 3rd degree atrioventricular block, or sick sinus syndrome.
Reported side effects of Beta-blockers include, but not limited to dizziness, weakness, drowsiness, fatigue, cold hands and feet, dry mouth, dry skin, dry eyes, headache, stomach upset, diarrhoea, constipation, depression, shortness of breath, wheezing, trouble breathing, loss of sex drive, erectile dysfunction, trouble sleeping, swelling of the hands or feet, slow heartbeat, skin rash, memory loss, confusion, back pain, joint pain.
Diuretics reduce blood pressure by decreasing fluid volume in the body, in which sodium and water are excreted from the body as urine. Diuretics help decrease plasma volume and reduce vascular resistance through the shift of sodium from intracellular to extracellular loci. There are 3 types of Diuretics. They are the Thiazide Diuretics, Loop Diuretics, and Potassium Sparring Diuretics. Thiazide Diuretics generally have longer half-lives. Thiazide Diuretics may elevate serum LDL cholesterol, triglyceride levels, and decrease serum potassium leading to hypokalemia. Loop Diuretics are used for hypertension management in which patients have lost more than 50% kidney function. Potassium Sparing Diuretics do not cause hypokalemia, hyperuricemia, or hyperglycemia, but they are not as effective as Thiazide Diuretics in hypertension management.
Reported side effects of Diuretics include, but not limited to dizziness, headache, thirstiness, rash, itching, elevated blood glucose levels, higher cholesterol levels, higher triglyceride levels, sexual dysfunction, muscle cramps, ringing in the ears, low sodium levels, low potassium levels, low magnesium levels, enlarged breasts in men. Examples of Thiazide Diuretics are Microzide (hydrochlorothiazide), Thalitone (chlorthalidone), Zaroxolyn (metolazone).
Examples of Loop Diuretics are Lasix (furosemide), Demadex (torsemide), and Edecrin (ethacrynic acid). Examples of Potassium Sparring Diuretics are Aldactone (spironolactone), Inspra (eplerenone), Dyrenium (triamterene), and Midamor (amiloride).
ACE Inhibitors decrease blood pressure by interfering the conversion of angiotensin I to angiotensin II. ACE Inhibitors provide renal protection therefore they are the preferred drugs for patients with diabetes. They are not recommended for initial treatment in blacks mainly due to increased risks of stroke when used for initial treatment. Persistent dry cough is the most common side effect of ACE Inhibitors. Nevertheless, angioedema is the most serious side effect when it affects the oropharynx, which may be fatal. Angioedema is most common among blacks and smokers. ACE Inhibitors are one of the antihypertensives that least likely to cause erectile dysfunction. ACE Inhibitors are contraindicated during pregnancy. ACE Inhibitors can cause acute kidney injury in patients who have hypovolemia, severe heart failure, severe bilateral renal artery stenosis, or severe stenosis in the artery to a solitary kidney.
Reported side effects of ACE Inhibitors include, but not limited to dizziness, lightheadedness, rapid heartbeat, headache, loss of appetite, salty or metallic taste in mouth, stomach upset, diarrhoea, fatigue, fever, numbness, joint pain, skin rash, blisters, dry cough.
Examples of beta-blockers are Lotensin (benazepril), Capoten (captopril), Vasotec (enalapril), Zestril (lisinopril), Univasc (moexipril), Aceon (perindopril), Altace (ramipril), and Mavik (trandolapril).
Angiotensin II Receptor Blockers
Angiotensin II Receptor Blockers reduce blood pressure by blocking angiotensin II receptors therefore interfere with the Renin-Angiotensin-Aldosterone System. Angiotensin II Receptor Blockers and ACE Inhibitors can be equally effective as antihypertensive agents. Precautions for use of Angiotensin II Receptor Blockers in patients with hypovolemia, renovascular hypertension, and severe heart failure are the same as those for ACE Inhibitors. Angiotensin II Receptor Blockers are contraindicated during pregnancy.
Reported side effects of Angiotensin II Receptor Blockers include, but not limited to dizziness, headache, nausea, vomiting, Diarrhoea, muscle pain, bone pain, sudden drop in blood pressure upon standing, fatigue, high potassium levels in blood, rash.
Examples of Angiotensin II Receptor Blockers are Atacand (candesartan), Teveten (eprosartan), Benicar (olmesartan), Micardis (telmisartan), Micardis Plus (telmisartan with hydrochlorothiazide), Cozaar (losartan), Avapro (irbesartan), Avalide (irbesartan with hydrochlorothiazide), Hyzaar (losartan with hydrochlorothiazide), and Diovan (valsartan).
Calcium Channel Blockers
Calcium Channel Blockers reduce blood pressure by inhibiting calcium ions from entering into the cells of the heart and blood vessel walls. In the peripheral arterial smooth muscle cells and the heart, inhibition of calcium ions entry blunt the ability of calcium ions to serve as an intracellular messenger. Therefore, Calcium Channel Blockers are smooth muscle cells dilators and have a negative inotropic effect on the working myocardial cells of the atria and ventricles.
Reported side effects of Calcium Channel Blockers include, but not limited to dizziness, hands and feet swelling, rapid weight gain, reduced urine, new or worsened chest pain, fever, chills, sore throat, body aches, flu symptoms, elevated potassium levels, nausea, slow heart rate, weakness, liver problems, stomach pain, itching, fatigue, loss of appetite, dark urine, clay colour stools, jaundice.
Renin Inhibitors decrease blood pressure by inhibiting the activation of Renin Angiotensin Aldosterone System. As with ACE Inhibitors and Angiotensin II Receptor Blockers, Renin Inhibitors can increase serum potassium and creatinine levels. Renin Inhibitors should not be used along with ACE Inhibitors or Angiotensin II Receptor Blockers in patients with diabetes or renal disease (estimated GFR < 60 mL/min).
Reported side effects of Renin Inhibitors include, but not limited to dizziness, headache, fatigue, cough, diarrhoea, back pain, flu symptoms.
Examples of Renin Inhibitors are Tekturna, Rasilez (aliskiren).