Different BP Meds and Sideeffects
They help eliminate excess salt and water from the body by inhibiting reabsorption of sodium and chloride in the kidneys. They also decrease calcium excretion.
Diuretics are used to treat edema (abnormal accumulation of fluid) and to prevent, treat or improve symptoms associated with congestive heart failure (CHF), kidney dysfunction, kidney stones, liver cirrhosis, glaucoma, etc. Thiazide-type diuretics are preferred first-line treatments for most people with high blood pressure either administered as a single drug or adjunctively with other antihypertensive drugs.
Nephrons are the functional units of the kidneys and the renal tubules are a part of these nephrons. A tubule of the kidney is divided into proximal convoluted tubule (PCT), Loop of Henle and distal convoluted tubule (DCT). Various types of diuretics act at different sites of the kidney tubule.
Loop diuretics like furosemide are the most potent diuretic. They act at the loop of Henle and inhibit reabsorption of sodium and chloride into the body.
Thiazide diuretics like hydrochlorothiazide inhibit the reabsorption of sodium and chloride in the distal convoluted tubules.
Potassium-sparing diuretics like spironolactone, amiloride, etc. promote elimination of sodium and water by either interfering with the sodium-potassium exchange at the distal convoluted tubules or by blocking the effect of aldosterone hormone.
Carbonic anhydrase inhibitors like acetazolamide inhibit the enzyme carbonic anhydrase found in the proximal convoluted tubule thereby increasing accumulation of bicarbonate in the urine which in turn decreases sodium and water reabsorption in the body.
There are certain substances like mannitol whose presence in the fluid filtered by the kidney can cause additional water to come into the urine. Such substances are called osmotic diuretics. They increase urination and prevent the reabsorption of water, sodium and chloride.
Some of the side effects of diuretics include dehydration, increased thirst, frequent urination, weakness, fatigue, muscle cramps, blurred vision, dizziness, headache, etc. Men may have erection problems.
Diuretics should not be used in patients with known drug hypersensitivity
They are also contraindicated in patients with electrolyte imbalance.
They are ruled out in a patient with gout as they can aggravate the condition.
Drug interactions may occur with non-steroidal anti-inflammatory agents, corticosteroids, anticonvulsants, etc.
Diuretics must be used cautiously in people with renal dysfunction, diabetes or liver disease.
2. Ace Inhibitors
The amount of salt and water retention in the body is increased by the renin-angiotensin system in the kidney. This retention increases blood pressure. ACE inhibitors (angiotensin-converting-enzyme inhibitor) prevent the formation of angiotensin by inhibiting the angiotensin-converting enzyme, an important factor of this system. They also relax the blood vessel, reduce blood volume, decrease the amount of blood pumped by the heart (cardiac output) and increase sodium excretion in the urine thereby lowering blood pressure. Captopril, Enalapril, Fosinopril, Ramipril, Benazepril, etc. are some of the common drugs in this class.
ACE inhibitors are used alone or in combination with other antihypertensive drugs in the treatment of high blood pressure. They are also used in the treatment of heart attack (acute myocardial infarction), heart failure, diabetic nephropathy (a complication of diabetes affecting the kidneys), chronic kidney failure, scleroderma due to kidney involvement and migraine.
This class of drugs may cause skin rash, loss of taste and cough.
There is a probability of kidney impairment associated with the use of ACE inhibitors.
The drug’s depressing effect on aldosterone levels may cause elevated blood potassium levels.
It also increases bradykinin level leading to adverse symptoms like swelling in the skin and lining of body cavities and internal organs (angioedema), inflammation-related pain, low blood pressure, etc.
ACE inhibitors should not be taken along with nonsteroidal anti-inflammatory drugs (NSAIDs) and drugs that promote the production of urine (diuretics) due to the increased risk of developing kidney failure.
It should be avoided in pregnant women as it can cause birth defects, stillbirths, and deaths of newborns.
This group of antihypertensive drugs is not used in patients with hypersensitivity to the drug
They are also not used in those with narrowing of arteries of the kidney (renal artery stenosis).
Some foods and drugs may potentially interact with ACE inhibitors. Concomitant use of salt substitutes and ACE inhibitors can cause abnormally high levels of potassium in the blood (hyperkalemia). Nonsteroidal anti-inflammatory medications (NSAIDs) may decrease the effect of ACE inhibitors.
3. Angiotensin Ii Receptor Blockers
Angiotensin is a hormone which causes blood vessel constriction and sodium retention. Angiotensin II receptor blockers block binding of angiotensin-II to their receptors and antagonize its action. Some of the drugs may increase the excretion of uric acid in the urine. Candesartan, irbesartan, losartan, fimasartan olmesartan, telmisartan, etc. are few examples of drugs in this class.
Angiotensin II receptor blockers are used in the treatment of high blood pressure (hypertension). They may also help slow down the progression of kidney disease due to diabetes (diabetic nephropathy).
Common adverse effects may include dizziness, headache, rash, metallic taste sensation, indigestion, diarrhea, increased blood potassium levels, muscle cramp, etc. Rarely the drugs may cause liver failure and tissue swelling (angioedema).
These drugs are contraindicated in pregnancy.
4. Calcium Channel Blockers
Calcium channel blockers are drugs that interfere with the movement of calcium into the muscles in the heart and blood vessels. They bind to calcium channels in the blood vessels or the SA and AV nodes of the heart and block the entry of calcium. This results in dilatation of blood vessel, slowing of the conduction of electrical impulse in the heart or reduction of force of heart’s contraction which in turn decreases blood pressure. Nifedipine, amlodipine, diltiazem, etc. are some of the calcium channel blockers.
They are used in the treatment of hypertension (high blood pressure), arrhythmia (irregular heart beat) and angina (chest pain due to reduced blood to the heart muscle).
Side effects may include digestive problems, nausea, low BP, dizziness, headache, drowsiness, etc. They may also cause gum enlargement with bleeding. Calcium channel blockers are known to cause headaches, edema (accumulation of excessive fluid in the tissues), constipation and dizziness. When in doubt, clear all your hypertension queries with your doctor.
Hypersensitivity to the drug
Congestive heart failure or coronary artery disease
Grapefruit juice should be avoided with most drugs in this class as it affects the metabolism of drugs.
5. Adrenergic Receptor Blockers (Anti-Adrenergics)
This class of drugs acts on either the alpha or beta type of receptors and are accordingly called alpha blockers or beta blockers. Alpha blockers block the action of the nervous system on the blood vessels and this prevents the arteries from growing narrow. Beta-blockers reduce the heart rate, slow down the strength of each heart contraction and also inhibit production of angiotensin, leading to a drop in blood pressure.
Adrenergic receptor blockers can be
A. Alpha blockers – act on the alpha receptors
Alpha-1 blockers prevent nerve signals from increasing the heart rate and narrowing the blood vessels. Alpha-2 blockers act at the central nervous system of the brain to block the release of adrenaline (epinephrine) and noradrenaline (norepinephrine) which causes decreased stimulation of the blood vessels and the heart. This effect slows the heartbeat and contraction and also relaxes the blood vessels thereby decreasing blood pressure. Some of the drugs in this group are clonidine, α-methyldopa, guanfacine, etc.
B. Beta blockers – act on the beta receptors
beta-1 blocker (cardio-selective beta blockers)
Beta-adrenergic receptors present on the nerve system mediate the fight-or-flight response (sympathetic nervous system). There are three types of beta receptors labeled as β1, β2 and β3 receptors. Beta 1 (β1) receptors are predominant in the heart and kidney. Beta 2 (β2) receptors are predominant in the lungs and beta 3 (β3) receptors in fat cells. Beta-adrenergic blockers (beta blockers or β-blockers) prevent stimulation of these receptors and weaken the effects of adrenaline and noradrenaline. They reduce renin-angiotensin-aldosterone system activity in kidney by inhibiting the release of renin. They decrease the activity of the heart and constrict the smooth muscles. Some beta blockers block all the β-adrenergic receptors and others selectively block β1, β2 or β3 receptors. Cardio-selective beta blockers selectively block β1 receptors and mainly affect the heart. They decrease the force and rate of heart contraction and decrease blood pressure in the arteries. Since lungs have predominantly β2 receptors, their effect of bronchial constriction is decreased. Propranolol, Sotalol, Oxprenolol, Bucindolol, etc. are some of the beta blockers. Examples of cardio-selective beta blockers are Atenolol, Metoprolol, Bisoprolol, etc.
Alpha blockers are most commonly used in conjunction with diuretics to treat hypertension. They are also used to treat anxiety and panic disorders, Raynaud’s disease, scleroderma, and to treat the symptoms of BPH (benign prostatic hyperplasia).
Beta blockers are used for the management of angina, irregular heartbeat, hypertension, and to relieve some of the symptoms of an overactive thyroid (hyperthyroidism). Cardio-selective beta blockers are used in patients with heart disease and concomitant obstructive lung diseases.
Adverse effects of alpha blockers include dry mouth, nausea, dizziness, nasal congestion, headache, fluid retention, orthostatic hypotension (sudden drop in blood pressure when you stand up), heart palpitations, very low heart rate, etc.
Beta blockers may cause nausea, shortness of breath, diarrhea, decreased heart rate, low blood pressure, dizziness, sleep disturbances, swelling, decreased glucose levels (hypoglycemia), increased potassium levels (hyperkalemia), etc. as adverse effects. People taking beta-blockers may show asthma symptoms or may suffer from depression.
Beta blockers are not prescribed in patients with high cholesterol levels as they tend to increase levels of triglycerides as well as decrease the ‘good’ HDL cholesterol.
They are not recommended for the treatment of cocaine or other stimulant overdoses.
Beta blockers can aggravate asthma or chronic bronchitis and mask the dangerous decrease of blood sugar in diabetic patients.
Vasodilators are drugs that relax the walls of the blood vessels, decrease their resistance and improve blood flow. They help lower blood pressure and reduce heart workload. They are available in the form of sprays, skin patches, ointments and tablets, and are usually prescribed in combination with other medications.
Myotropic agents like sodium nitroprusside, papaverine, etc. dilate the blood vessel by directly affecting its muscle. Neurotropic agents like phentolamine regulate the nerve supplying the blood vessel to cause vasodilation. Cerebral vasodilators like papaverine, cinnarizine, etc. improve cerebral blood flow by dilating arteries in the brain. Peripheral vasodilators are drugs that have their effect on the blood vessels in the peripheral or outer parts of the body. They include nitrates, diuretics, ACE inhibitors, angiotensin II blockers, calcium channel blockers and alpha-blockers. Most drugs affect both arteries and veins. Drugs that work only on arteries are called arterial dilators, and those that work on veins are called venous dilators.
Vasodilators, like relax the walls of the arteries and improve blood flow.
Vasodilators are used to treat symptoms of high blood pressure, angina and congestive heart failure. They are used for quick, temporary relief in hypertensive emergencies.
Some of the side effects associated with this group of drugs are headache, dizziness, nausea, stomach upset, nasal congestion, flushing, rapid heartbeat (tachycardia) and changes in heart rhythm.
Vasodilators may be contraindicated in patients with severe aortic stenosis and coronary artery disease.
Overdose can result in severe low blood pressure and reflex tachycardia (increased heart rate) with a lack of blood flow to the heart.
7. Renin Inhibitors
The renin-angiotensin system increases the amount of salt and water retention in the body. This retention increases blood pressure. Renin inhibitors like aliskiren inhibit the enzyme renin and prevent it from catalyzing the reactions that result in the formation of angiotensin; decreased angiotensin production means reduced blood pressure. Currently, aliskiren is the only commercial available renin inhibitor.
Renin inhibitors are primarily used in the treatment of high blood pressure.
The drug can cause diarrhea, headache, dizziness, angioedema (swelling of the face, mouth and throat due to an allergic reaction), high blood potassium level, etc.
Contraindicated in pregnancy
Not recommended as drug combinations with ACE inhibitors and angiotensin receptor blockers in patients with diabetes or kidney impairment
Concomitant use with cyclosporine
The drug should be used cautiously in patients with kidney disease. Caution should be used when salt substitutes are consumed.
8. Aldosterone Receptor Antagonists
Aldosterone hormone interferes with sodium/potassium exchange in the kidneys to increase sodium re-absorption and potassium excretion. Aldosterone blockers or aldosterone receptor antagonists (mineralocorticoid receptor antagonists) block the action of aldosterone by competing with the hormone. This blockage leads to decreased sodium re-absorption and water retention by the kidneys. Aldosterone receptor antagonists include eplerenone, spironolactone, etc.
They are used to treat hypertension and for the management of chronic heart failure. Spironolactone may also be used to treat resistant hypertension and in the management of hyperaldosteronism (increased aldosterone production by the adrenal glands) and hirsutism (excessive hairiness on women).
This group of drugs may cause side effects like increased blood potassium levels (hyperkalaemia), increased urination, tiredness, dizziness, altered kidney function, low blood pressure, etc. Spironolactone can also cause an increase in the size of breast (gynecomastia), loss of libido and impotence in men and breast tenderness, menstrual irregularities, etc. in women.
Hypersensitivity to the drug
Use with caution in kidney disease
Concomitant use of salt substitutes should be avoided
9. Endothelin Receptor Blockers
An excess endothelin is produced in pulmonary artery hypertension (PAH). This increase causes constriction of blood vessels and affects the blood pressure in the lungs. Endothelin receptor blockers block the endothelin receptors, thereby limiting activation of endothelin.
Endothelin receptor blockers like bosentan are used in the treatment of pulmonary arterial hypertension.
Side effects include stuffy nose, headache, nausea, reduced urination, swelling in the extremities, flushing, palpitations, hypotension, etc.
Contraindicated in pregnancy
In patients treated with bosentan, the liver function needs to be monitored. more