The antihypertensives are a class of drugs

Medication

A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...

 that are used to treat hypertension

Hypertension

Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...

 (high blood pressure). Evidence suggests that reduction of the blood pressure

Blood pressure

Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...

 by 5 mmHg can decrease the risk of stroke by 34%, of ischaemic heart disease

Ischaemic heart disease

Ischaemic or ischemic heart disease , or myocardial ischaemia, is a disease characterized by ischaemia of the heart muscle, usually due to coronary artery disease...

 by 21%, and reduce the likelihood of dementia

Dementia

Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging...

, heart failure, and mortality

Death

Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....

 from cardiovascular disease

Cardiovascular disease

Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...

. There are many classes of antihypertensives, which lower blood pressure by different means; among the most important and most widely used are the thiazide

Thiazide

Thiazide is a term used to describe a type of molecule and a class of diuretics often used to treat hypertension and edema ....

 diuretic

Diuretic

A diuretic provides a means of forced diuresis which elevates the rate of urination. There are several categories of diuretics. All diuretics increase the excretion of water from bodies, although each class does so in a distinct way.- Medical uses :...

s, the ACE inhibitor

ACE inhibitor

ACE inhibitors or angiotensin-converting enzyme inhibitors are a group of drugs used primarily for the treatment of hypertension and congestive heart failure...

s, the calcium channel blocker

Calcium channel blocker

A calcium channel blocker is a chemical that disrupts the movement of calcium through calcium channels.CCB drugs devised to target neurons are used as antiepileptics. However, the most widespread clinical usage of calcium channel blockers is to decrease blood pressure in patients with...

s, the beta blocker

Beta blocker

Beta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...

s, and the angiotensin II receptor antagonist

Angiotensin II receptor antagonist

Angiotensin II receptor antagonists, also known as angiotensin receptor blockers , AT1-receptor antagonists or sartans, are a group of pharmaceuticals which modulate the renin-angiotensin-aldosterone system...

s or ARBs.

Which type of medication to use initially for hypertension has been the subject of several large studies and resulting national guidelines. The fundamental goal of treatment should be the prevention of the important endpoints

Clinical endpoint

In a clinical research trial, a clinical endpoint generally refers to occurrence of a disease, symptom, sign or laboratory abnormality that constitutes one of the target outcomes of the trial, but may also refer to any such disease or sign that strongly motivates the withdrawal of that individual...

 of hypertension

Hypertension

Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...

, such as heart attack, stroke and heart failure. Patient age, associated clinical conditions and end-organ damage also play a part in determining dosage and type of medication administered. The several classes of antihypertensives differ in side effect profiles, ability to prevent endpoints, and cost. The choice of more expensive agents, where cheaper ones would be equally effective, may have negative impacts on national healthcare budgets. As of 2009, the best available evidence

Evidence-based medicine

Evidence-based medicine or evidence-based practice aims to apply the best available evidence gained from the scientific method to clinical decision making. It seeks to assess the strength of evidence of the risks and benefits of treatments and diagnostic tests...

 favors the thiazide diuretics as the first-line treatment of choice for high blood pressure when drugs are necessary.

Diuretics

Diuretic

Diuretic

A diuretic provides a means of forced diuresis which elevates the rate of urination. There are several categories of diuretics. All diuretics increase the excretion of water from bodies, although each class does so in a distinct way.- Medical uses :...

s help the kidneys eliminate excess salt and water from the body's tissues and blood.

• Loop diuretic
  Loop diuretic
  Loop diuretics are diuretics that act on the ascending loop of Henle in the kidney. They are primarily used in medicine to treat hypertension and edema often due to congestive heart failure or renal insufficiency...
  
  s:
  • bumetanide
    Bumetanide
    Bumetanide is a loop diuretic of the sulfamyl category to treat heart failure. It is often used in people in whom high doses of furosemide are ineffective. It is marketed by Hoffmann-La Roche. The main difference between the two substances is in bioavailability and pharmacodynamic potency...
    
    
  • ethacrynic acid
    Ethacrynic acid
    Etacrynic acid or ethacrynic acid , trade name Edecrin, is a loop diuretic used to treat high blood pressure and the swelling caused by diseases like congestive heart failure, liver failure, and kidney failure....
    
    
  • furosemide
    Furosemide
    Furosemide or frusemide is a loop diuretic used in the treatment of congestive heart failure and edema. It is most commonly marketed by Sanofi-Aventis under the brand name Lasix...
    
    
  • torsemide
• Thiazide
  Thiazide
  Thiazide is a term used to describe a type of molecule and a class of diuretics often used to treat hypertension and edema ....
  
   diuretics:
  • epitizide
    Epitizide
    Epitizide is a diuretic....
    
    
  • hydrochlorothiazide
    Hydrochlorothiazide
    Hydrochlorothiazide, abbreviated HCTZ, HCT, or HZT, is a first-line diuretic drug of the thiazide class that acts by inhibiting the kidneys' ability to retain water. This reduces the volume of the blood, decreasing blood return to the heart and thus cardiac output and, by other mechanisms, is...
    
     and chlorothiazide
    Chlorothiazide
    Chlorothiazide sodium is a diuretic used within the hospital setting or for personal use to manage excess fluid associated with congestive heart failure. It is also used as an antihypertensive....
    
    
  • bendroflumethiazide
    Bendroflumethiazide
    Bendroflumethiazide , formerly bendrofluazide , is a thiazide diuretic used to treat hypertension.It is also a fairly cheap drug, made cheap through mass production...
    
    
• Thiazide-like diuretics:
  • indapamide
    Indapamide
    Indapamide is a thiazide diuretic drug marketed by Servier, generally used in the treatment of hypertension, as well as decompensated cardiac failure. The US trade name for indapamide is Lozol. Indapamide is marketed as Natrilix outside of the US, as Insig in Australia...
    
    
  • chlorthalidone
  • metolazone
    Metolazone
    Metolazone is a thiazide-like diuretic marketed under the brand names Zytanix from Zydus Cadila, Zaroxolyn, and Mykrox. It is primarily used to treat congestive heart failure and high blood pressure. Metolazone indirectly decreases the amount of water reabsorbed into the bloodstream by the kidney,...
    
    
• Potassium-sparing diuretics:
  • amiloride
    Amiloride
    Amiloride is a potassium-sparing diuretic, first approved for use in 1967 , used in the management of hypertension and congestive heart failure. Amiloride was also tested as treatment of cystic fibrosis, but it was revealed inefficient in vivo due to it's short time of action, therefore...
    
    
  • triamterene
  • spironolactone
    Spironolactone
    Spironolactone , commonly referred to as simply spiro, is a diuretic and is used as an antiandrogen.It is a synthetic 17-lactone drug that is a renal competitive aldosterone antagonist in a class of pharmaceuticals called...
    
    

Only the thiazide

Thiazide

Thiazide is a term used to describe a type of molecule and a class of diuretics often used to treat hypertension and edema ....

 and thiazide-like diuretics have good evidence of beneficial effects on important endpoints of hypertension

Hypertension

Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...

, and hence, should usually be the first choice when selecting a diuretic to treat hypertension. The reason why thiazide-type diuretics are better than the others is (at least in part) thought to be because of their vasodilating properties. Although the diuretic effect of thiazides may be apparent shortly after administration, it takes longer (weeks of treatment) for the full anti-hypertensive effect to develop. In the United States, the JNC7 (The Seventh Report of the Joint National Committee on Prevention of Detection, Evaluation and Treatment of High Blood Pressure) recommends starting with a thiazide

Thiazide

Thiazide is a term used to describe a type of molecule and a class of diuretics often used to treat hypertension and edema ....

 diuretic if single therapy is being initiated and another medication is not indicated.
This is based on a slightly better outcome for chlortalidone

Chlortalidone

Chlortalidone or chlorthalidone is a diuretic drug used to treat hypertension, originally marketed as Hygroton in the USA. It is described as a thiazide diuretic...

 in the ALLHAT study versus other anti-hypertensives and because thiazide diuretics are relatively cheap.
A subsequent smaller study (ANBP2) published after the JNC7 did not show this small difference in outcome and actually showed a slightly better outcome for ACE-inhibitors in older male patients.

Despite thiazides being cheap, effective, and recommended as the best first-line drug for hypertension by many experts, they are not prescribed as often as some newer drugs. This is because they have been associated with increased risk of new-onset diabetes and as such are recommended for use in patients over 65 where the risk of new-onset diabetes is outweighed by the benefits of controlling systolic blood pressure

Another theory is that they are off-patent and thus rarely promoted by the drug industry.

Adrenergic receptor antagonists

• Beta blocker
  Beta blocker
  Beta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...
  
  s
  • atenolol
  • metoprolol
    Metoprolol
    Metoprolol is a selective β1 receptor blocker used in treatment of several diseases of the cardiovascular system, especially hypertension. The active substance metoprolol is employed either as metoprolol succinate or metoprolol tartrate...
    
    
  • nadolol
    Nadolol
    Nadolol is a non-selective beta blocker used in the treatment of high blood pressure, migraine headaches, and chest pain.-Pharmacology:...
    
    
  • oxprenolol
    Oxprenolol
    Oxprenolol is a non-selective beta blocker with some intrinsic sympathomimetic activity...
    
    
  • pindolol
    Pindolol
    Pindolol is a beta blocker....
    
    
  • propranolol
  • timolol
    Timolol
    Timolol maleate is a non-selective beta-adrenergic receptor blocker.-Uses:In its oral form , it is used:* to treat high blood pressure* to prevent heart attacks* to prevent migraine headaches...
    
    
• Alpha blocker
  Alpha blocker
  Alpha-1 blockers constitute a variety of drugs which block α1-adrenergic receptors in arteries and smooth muscles.-Pharmacology:...
  
  s:
  • doxazosin
    Doxazosin
    Doxazosin mesylate, a quinazoline compound sold by Pfizer under the brand names Cardura and Carduran, is an α1a-selective alpha blocker used to treat high blood pressure and urinary retention associated with benign prostatic hyperplasia ....
    
    
  • phentolamine
    Phentolamine
    Phentolamine is a reversible nonselective alpha-adrenergic antagonist. -Mechanism:Its primary action is vasodilation due to α1 blockade....
    
    
  • indoramin
    Indoramin
    Indoramin is a piperidine antiadrenergic agent.It is an alpha-1 selective adrenoceptor antagonist. with direct myocardial depression action,therefore,it results in no reflex tachycardiaIt is commonly synthesized from tryptophol...
    
    
  • phenoxybenzamine
    Phenoxybenzamine
    Phenoxybenzamine is a non-selective, irreversible alpha antagonist.-Uses:It is used in the treatment of hypertension, and specifically that caused by pheochromocytoma...
    
    
  • prazosin
    Prazosin
    Prazosin, trade names Minipress, Vasoflex, Pressin and Hypovase, is a sympatholytic drug used to treat high blood pressure and Anxiety, PTSD and Panic Disorder. It belongs to the class of alpha-adrenergic blockers. Specifically, prazosin is selective for the alpha-1 receptors on vascular smooth...
    
    
  • terazosin
    Terazosin
    Terazosin is a selective alpha 1 antagonist used for treatment of symptoms of an enlarged prostate...
    
    
  • tolazoline
    Tolazoline
    Tolazoline is a non-selective competitive α-adrenergic receptor antagonist. It is a vasodilator that is used to treat spasms of peripheral blood vessels...
    
    
• Mixed Alpha + Beta blockers:
  • bucindolol
    Bucindolol
    Bucindolol is a non-selective beta blocker with additional weak alpha-blocking properties and some intrinsic sympathomimetic activity. It was under review by the FDA in the United States for the treatment of heart failure in 2009 ....
    
    
  • carvedilol
    Carvedilol
    Carvedilol is a non-selective beta blocker/alpha-1 blocker indicated in the treatment of mild to moderate congestive heart failure . It is marketed under various trade names including Carvil , Coreg , Dilatrend , Eucardic , and Carloc as a generic drug ., and as a...
    
    
  • labetalol
    Labetalol
    Labetalol is a mixed alpha/beta adrenergic antagonist, which is used to treat high blood pressure.-Indications:...
    
    

Although beta blocker

Beta blocker

Beta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...

s lower blood pressure, they do not have a positive benefit on endpoints as some other antihypertensives. In particular, beta-blockers are no longer recommended as first-line treatment due to relative adverse risk of stroke and new-onset diabetes when compared to other medications, while certain specific beta-blockers such as atenolol appear to be less useful in overall treatment of hypertension than several other agents. They do, however, have an important role in the prevention of heart attacks in people who have already had a heart attack. In the United Kingdom, the June 2006 "Hypertension: Management of Hypertension in Adults in Primary Care" guideline of the National Institute for Health and Clinical Excellence

National Institute for Health and Clinical Excellence

The National Institute for Health and Clinical Excellence is a special health authority of the English National Health Service , serving both English NHS and the Welsh NHS...

, downgraded the role of beta-blockers due to their risk of provoking type 2 diabetes.

Despite lowering blood pressure, alpha blocker

Alpha blocker

Alpha-1 blockers constitute a variety of drugs which block α1-adrenergic receptors in arteries and smooth muscles.-Pharmacology:...

s have significantly poorer endpoint outcomes than other antihypertensives, and are no longer recommended as a first-line choice in the treatment of hypertension.
However, they may be useful for some men with symptoms of prostate disease

Benign prostatic hyperplasia

Benign prostatic hyperplasia also known as benign prostatic hypertrophy , benign enlargement of the prostate , and adenofibromyomatous hyperplasia, refers to the increase in size of the prostate....

.

Calcium channel blockers

Calcium channel blocker

Calcium channel blocker

A calcium channel blocker is a chemical that disrupts the movement of calcium through calcium channels.CCB drugs devised to target neurons are used as antiepileptics. However, the most widespread clinical usage of calcium channel blockers is to decrease blood pressure in patients with...

s block the entry of calcium into muscle cells in artery walls.

• dihydropyridines:
  • amlodipine
    Amlodipine
    Amlodipine is a long-acting calcium channel blocker used as an anti-hypertensive and in the treatment of angina...
    
    
  • felodipine
    Felodipine
    Felodipine is a calcium channel blocker , a drug used to control hypertension . It is marketed under the brand name Plendil by AstraZeneca and Renedil by Sanofi-Aventis...
    
    
  • isradipine
    Isradipine
    Isradipine is a calcium channel blocker of the dihydropyridine class. It is usually prescribed for the treatment of high blood pressure in order to reduce the risk of stroke and heart attack...
    
    
  • lercanidipine
    Lercanidipine
    Lercanidipine is a calcium channel blocker of the dihydropyridine class.It is sold under various commercial names including Zanidip,which works by relaxing and opening the blood vessels allowing the blood to circulate more freely around the body. This lowers the blood pressure and allows the heart...
    
    
  • nicardipine
    Nicardipine
    Nicardipine hydrochloride is a medication used to treat high blood pressure and angina. It belongs to the class of calcium channel blockers....
    
    
  • nifedipine
    Nifedipine
    Nifedipine is a dihydropyridine calcium channel blocker...
    
    
  • nimodipine
    Nimodipine
    Nimodipine is a dihydropyridine calcium channel blocker originally developed for the treatment of high blood pressure...
    
    
  • nitrendipine
    Nitrendipine
    Nitrendipine is a dihydropyridine calcium channel blocker. It is used in the treatment of primary hypertension to decrease blood pressure....
    
    
• non-dihydropyridines:
  • diltiazem
    Diltiazem
    Diltiazem is a non-dihydropyridine member of the class of drugs known as calcium channel blockers, used in the treatment of hypertension, angina pectoris, and some types of arrhythmia....
    
    
  • verapamil
    Verapamil
    Verapamil is an L-type calcium channel blocker of the phenylalkylamine class. It has been used in the treatment of hypertension, angina pectoris, cardiac arrhythmia, and most recently, cluster headaches. It is also an effective preventive medication for migraine...
    
    

Renin Inhibitors

Renin comes one level higher than Angiotensin Converting Enzyme (ACE) in the Renin-Angiotensin System. Inhibitors of renin can therefore effectively reduce hyptertension. Aliskiren (developed by Novartis) is a renin inhibitor which has been approved by the US-FDA for treatment of hypertension.

ACE inhibitors

ACE inhibitor

ACE inhibitor

ACE inhibitors or angiotensin-converting enzyme inhibitors are a group of drugs used primarily for the treatment of hypertension and congestive heart failure...

s inhibit the activity of Angiotensin-converting enzyme

Angiotensin-converting enzyme

Angiotensin I-converting enzyme , an exopeptidase, is a circulating enzyme that participates in the body's renin-angiotensin system , which mediates extracellular volume , and arterial vasoconstriction...

 (ACE), an enzyme responsible for the conversion of angiotensin I into angiotensin

Angiotensin

Angiotensin, a peptide hormone, causes blood vessels to constrict, and drives blood pressure up. It is part of the renin-angiotensin system, which is a major target for drugs that lower blood pressure. Angiotensin also stimulates the release of aldosterone, another hormone, from the adrenal cortex...

 II, a potent vasoconstrictor.

• captopril
  Captopril
  Captopril is an angiotensin-converting enzyme inhibitor used for the treatment of hypertension and some types of congestive heart failure. Captopril was the first ACE inhibitor developed and was considered a breakthrough both because of its novel mechanism of action and also because of the...
  
  
• enalapril
  Enalapril
  Enalapril is an angiotensin converting enzyme inhibitor used in the treatment of hypertension and some types of chronic heart failure. ACE raises blood pressure by constricting blood vessels. ACE inhibitors like enalapril prevent this effect. Enalapril has been shown to lower the death rate in...
  
  
• fosinopril
  Fosinopril
  Fosinopril is an angiotensin converting enzyme inhibitor used for the treatment of hypertension and some types of chronic heart failure. Fosinopril is the only phosphinate-containing ACE inhibitor marketed...
  
  
• lisinopril
  Lisinopril
  Lisinopril is a drug of the angiotensin-converting enzyme inhibitor class that is primarily used in treatment of hypertension, congestive heart failure, and heart attacks and also in preventing renal and retinal complications of diabetes. Its indications, contraindications and side effects are as...
  
  
• perindopril
  Perindopril
  Perindopril, or perindopril arginine, is a long-acting ACE inhibitor. Perindopril is used to treat high blood pressure, heart failure or stable coronary artery disease. It is also available in a generic form, perindopril erbumine...
  
  
• quinapril
  Quinapril
  Quinapril is an angiotensin-converting enzyme inhibitor used in the treatment of hypertension and congestive heart failure.-Pharmacology:Quinapril is a prodrug...
  
  
• ramipril
  Ramipril
  Ramipril is an angiotensin-converting enzyme inhibitor, used to treat high blood pressure and congestive heart failure.-Mechanism of action:ACE inhibitors lower the...
  
  
• trandolapril
  Trandolapril
  Trandolapril is an ACE inhibitor used to treat high blood pressure, it may also be used to treat other conditions.It is marketed by Abbott Laboratories with the brand name Mavik.- Pharmacology :...
  
  
• benazepril
  Benazepril
  Benazepril, brand name Lotensin, is a medication used to treat high blood pressure , congestive heart failure, and chronic renal failure...
  
  

Angiotensin II receptor antagonists

Angiotensin II receptor antagonist

Angiotensin II receptor antagonist

Angiotensin II receptor antagonists, also known as angiotensin receptor blockers , AT1-receptor antagonists or sartans, are a group of pharmaceuticals which modulate the renin-angiotensin-aldosterone system...

s work by antagonizing

Receptor antagonist

A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...

 the activation of angiotensin receptor

Angiotensin receptor

The angiotensin receptors are a class of G protein-coupled receptors with angiotensin II as their ligands. They are important in the renin-angiotensin system: they are responsible for the signal transduction of the vasoconstricting stimulus of the main effector hormone, angiotensin...

s.

• candesartan
  Candesartan
  Candesartan is an angiotensin II receptor antagonist used mainly for the treatment of hypertension. The prodrug candesartan cilexetil is marketed by AstraZeneca and Takeda Pharmaceuticals, commonly under the trade names Blopress, Atacand, Amias, and Ratacand.-Clinical use:As all angiotensin II...
  
  
• eprosartan
  Eprosartan
  Eprosartan is an angiotensin II receptor antagonist used for the treatment of high blood pressure. It is marketed as Teveten by Abbott Laboratories in the United States.It is marketed as Eprozar by INTAS Pharmaceuticals in the INDIA and by Solvay Pharmaceuticals elsewhere...
  
  
• irbesartan
  Irbesartan
  Irbesartan is an angiotensin II receptor antagonist used mainly for the treatment of hypertension. Irbesartan was developed by Sanofi Research...
  
  
• losartan
  Losartan
  Losartan is an angiotensin II receptor antagonist drug used mainly to treat high blood pressure . Losartan was the first angiotensin II receptor antagonist to be marketed. Losartan potassium is marketed by Merck & Co. Inc. under the trade name Cozaar...
  
  
• olmesartan
  Olmesartan
  Olmesartan medoxomil is an angiotensin II receptor antagonist used to treat high blood pressure.-Indications:...
  
  
• telmisartan
  Telmisartan
  Telmisartan is an angiotensin II receptor antagonist used in the management of hypertension. It is marketed under the trade name Micardis , among others.-Administration:...
  
  
• valsartan
  Valsartan
  Valsartan is an angiotensin II receptor antagonist , with particularly high affinity for the type I angiotensin receptor. By blocking the action of angiotensin, valsartan dilates blood vessels and reduces blood pressure...
  
  

Aldosterone antagonists

Aldosterone

Aldosterone

Aldosterone is a hormone that increases the reabsorption of sodium ions and water and the release of potassium in the collecting ducts and distal convoluted tubule of the kidneys' functional unit, the nephron. This increases blood volume and, therefore, increases blood pressure. Drugs that...

 receptor antagonists:

• eplerenone
  Eplerenone
  Eplerenone is an aldosterone antagonist used as an adjunct in the management of chronic heart failure. It is similar to the diuretic spironolactone, though it may be more specific for the mineralocorticoid receptor and is specifically marketed for reducing cardiovascular risk in patients...
  
  
• spironolactone
  Spironolactone
  Spironolactone , commonly referred to as simply spiro, is a diuretic and is used as an antiandrogen.It is a synthetic 17-lactone drug that is a renal competitive aldosterone antagonist in a class of pharmaceuticals called...
  
  

Aldosterone

Aldosterone

Aldosterone is a hormone that increases the reabsorption of sodium ions and water and the release of potassium in the collecting ducts and distal convoluted tubule of the kidneys' functional unit, the nephron. This increases blood volume and, therefore, increases blood pressure. Drugs that...

 antagonists are not recommended as first-line agents for blood pressure, but spironolactone

Spironolactone

Spironolactone , commonly referred to as simply spiro, is a diuretic and is used as an antiandrogen.It is a synthetic 17-lactone drug that is a renal competitive aldosterone antagonist in a class of pharmaceuticals called...

 and eplerenone

Eplerenone

Eplerenone is an aldosterone antagonist used as an adjunct in the management of chronic heart failure. It is similar to the diuretic spironolactone, though it may be more specific for the mineralocorticoid receptor and is specifically marketed for reducing cardiovascular risk in patients...

 are both used in the treatment of heart failure.

Vasodilators

Vasodilators act directly on the smooth muscle

Smooth muscle

Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...

 of arteries to relax their walls so blood can move more easily through them; they are only used in hypertensive emergencies

Hypertensive emergency

Malignant hypertension or hypertensive emergency is severe hypertension with acute impairment of an organ system and the possibility of irreversible organ-damage...

 or when other drugs have failed, and even so are rarely given alone.

Sodium nitroprusside

Sodium nitroprusside

Sodium nitroprusside is the inorganic compound with the formula Na2[Fe5NO]·2H2O. This red-coloured salt, which is often abbreviated SNP, is a potent vasodilator...

, a very potent, short-acting vasodilator, is most commonly used for the quick, temporary reduction of blood pressure in emergencies (such as malignant hypertension

Malignant hypertension

Malignant hypertension or hypertensive emergency is severe hypertension with acute impairment of an organ system and the possibility of irreversible organ-damage...

 or aortic dissection

Aortic dissection

Aortic dissection occurs when a tear in the inner wall of the aorta causes blood to flow between the layers of the wall of the aorta and force the layers apart. The dissection typically extends anterograde, but can extend retrograde from the site of the intimal tear. Aortic dissection is a medical...

). Hydralazine

Hydralazine

Hydralazine is a direct-acting smooth muscle relaxant used to treat hypertension by acting as a vasodilator primarily in arteries and arterioles...

 and its derivatives are also used in the treatment of severe hypertension, although they should be avoided in emergencies. They are no longer indicated as first-line therapy for high blood pressure due to side effects and safety concerns, but hydralazine remains a drug of choice in gestational hypertension.

Alpha-2 agonists

Central alpha agonists lower blood pressure by stimulating alpha-receptors in the brain which open peripheral arteries easing blood flow. Central alpha agonists, such as clonidine, are usually prescribed when all other anti-hypertensive medications have failed. For treating hypertension, these drugs are usually administered in combination with a diuretic.

• Clonidine
  Clonidine
  Clonidine is a sympatholytic medication used to treat medical conditions, such as high blood pressure, some pain conditions, ADHD and anxiety/panic disorder...
  
  
• Guanabenz
  Guanabenz
  Guanabenz is an alpha agonist of the alpha-2 type that is used as an antihypertensive drug. It is used to treat high blood pressure ....
  
  
• Methyldopa
  Methyldopa
  Methyldopa is an alpha-adrenergic agonist psychoactive drug used as a sympatholytic or antihypertensive. Its use is now mostly deprecated following the introduction of alternative safer classes of agents...
  
  
• Moxonidine
  Moxonidine
  Moxonidine is a new generation centrally acting antihypertensive drug licensed for the treatment of mild to moderate essential hypertension. It may have a role when thiazides, beta-blockers, ACE inhibitors and calcium channel blockers are not appropriate or have failed to control blood pressure...
  
  

Adverse effects of this class of drugs include sedation, drying of the nasal mucosa and rebound hypertension.

Some adrenergic neuron blockers are used for the most resistant forms of hypertension:

• Guanethidine
  Guanethidine
  Guanethidine is an antihypertensive drug that reduces the release of catecholamines, such as norepinephrine. Guanethidine is transported across the sympathetic nerve membrane by the same mechanism that transports norepinephrine itself , and uptake is essential for the drug's action...
  
  
• Reserpine
  Reserpine
  Reserpine is an indole alkaloid antipsychotic and antihypertensive drug that has been used for the control of high blood pressure and for the relief of psychotic symptoms, although because of the development of better drugs for these purposes and because of its numerous side-effects, it is rarely...
  
  

Blood pressure vaccines

Blood pressure vaccinations are being trialed and may become a treatment option for high blood pressure in the future. CYT006-AngQb

CYT006-AngQb

CYT006-AngQb was an investigational vaccine against angiotensin II, designed to lower blood pressure. It was somewhat effective in clinical trials, but less so than conventional drugs against hypertension .-Method of action:...

 was only moderately successful in studies, but similar vaccines are being investigated.

Choice of initial medication

For mild blood pressure elevation, consensus guidelines call for medically supervised lifestyle changes and observation before recommending initiation of drug therapy. However, according to the American Hypertension Association, evidence of sustained damage to the body may be present even prior to observed elevation of blood pressure. Therefore the use of hypertensive medications may be started in individuals with apparent normal blood pressures but who show evidence of hypertension related nephropathy, proteinuria, atherosclerotic vascular disease, as well as other evidence of hypertension related organ damage.

If lifestyle changes are ineffective, then drug therapy is initiated, often requiring more than one agent to effectively lower hypertension.
Which type of many medications should be used initially for hypertension has been the subject of several large studies and various national guidelines.

The largest study, Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), concluded that thiazide-type diuretics are better and cheaper than other major classes of drugs at preventing cardiovascular disease, and should be preferred as the starting drug. ALLHAT used the thiazide diuretic chlorthalidone. (ALLHAT showed that doxazosin, an alpha-adrenergic receptor blocker, had a higher incidence of heart failure events, and the doxazosin arm of the study was stopped.)

A subsequent smaller study (ANBP2) did not show the slight advantages in thiazide diuretic outcomes observed in the ALLHAT study, and actually showed slightly better outcomes for ACE-inhibitors in older white male patients.

Thiazide diuretics are effective, recommended as the best first-line drug for hypertension by many experts, and are much more affordable than other therapies, yet they are not prescribed as often as some newer drugs. Hydrochlorothiazide

Hydrochlorothiazide

Hydrochlorothiazide, abbreviated HCTZ, HCT, or HZT, is a first-line diuretic drug of the thiazide class that acts by inhibiting the kidneys' ability to retain water. This reduces the volume of the blood, decreasing blood return to the heart and thus cardiac output and, by other mechanisms, is...

 is perhaps the safest and most inexpensive agent commonly used in this class and is very frequently combined with other agents in a single pill. Doses in excess of 25 milligrams per day of this agent incur an unacceptable risk of low potassium or Hypokalemia

Hypokalemia

Hypokalemia or hypokalaemia , also hypopotassemia or hypopotassaemia , refers to the condition in which the concentration of potassium in the blood is low...

. Patients with an exaggerated hypokalemic response to a low dose of a thiazide diuretic should be suspected to have Hyperaldosteronism

Hyperaldosteronism

Hyperaldosteronism, also aldosteronism, is a medical condition where too much aldosterone is produced by the adrenal glands, which can lead to lowered levels of potassium in the blood.-Types:...

, a common cause of secondary hypertension.

Other drugs have a role in treating hypertension. Adverse effects of thiazide diuretics include hypercholesterolemia

Hypercholesterolemia

Hypercholesterolemia is the presence of high levels of cholesterol in the blood. It is not a disease but a metabolic derangement that can be caused by many diseases, notably cardiovascular disease...

, and impaired glucose tolerance

Impaired glucose tolerance

Impaired glucose tolerance is a pre-diabetic state of dysglycemia that is associated with insulin resistance and increased risk of cardiovascular pathology. IGT may precede type 2 diabetes mellitus by many years...

 with increased risk of developing Diabetes mellitus type 2

Diabetes mellitus type 2

Diabetes mellitus type 2formerly non-insulin-dependent diabetes mellitus or adult-onset diabetesis a metabolic disorder that is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. Diabetes is often initially managed by increasing exercise and...

. The thiazide diuretics also deplete circulating potassium unless combined with a potassium-sparing diuretic

Potassium-sparing diuretic

Potassium-sparing diuretics are diuretic drugs that do not promote the secretion of potassium into the urine.They are used as adjunctive therapy, together with other drugs, in the treatment of hypertension and management of congestive heart failure....

 or supplemental potassium. Some authors have challenged thiazides as first line treatment. However as the Merck Manual of Geriatrics notes, "thiazide-type diuretics are especially safe and effective in the elderly."

Current UK guidelines suggest starting patients over the age of 55 years and all those of African/Afrocaribbean ethnicity firstly on calcium channel blockers or thiazide diuretics, whilst younger patients of other ethnic group

Ethnic group

An ethnic group is a group of people whose members identify with each other, through a common heritage, often consisting of a common language, a common culture and/or an ideology that stresses common ancestry or endogamy...

s should be started on ACE-inhibitors. Subsequently if dual therapy is required to use ACE-inhibitor in combination with either a calcium channel blocker or a (thiazide) diuretic. Triple therapy is then of all three groups and should the need arise then to add in a fourth agent, to consider either a further diuretic (e.g. spironolactone

Spironolactone

Spironolactone , commonly referred to as simply spiro, is a diuretic and is used as an antiandrogen.It is a synthetic 17-lactone drug that is a renal competitive aldosterone antagonist in a class of pharmaceuticals called...

 or furosemide

Furosemide

Furosemide or frusemide is a loop diuretic used in the treatment of congestive heart failure and edema. It is most commonly marketed by Sanofi-Aventis under the brand name Lasix...

), an alpha-blocker or a beta-blocker. Prior to the demotion of beta-blockers as first line agents, the UK sequence of combination therapy used the first letter of the drug classes and was known as the "ABCD rule".

The choice between the drugs is to a large degree determined by the characteristics of the patient being prescribed for, the drugs' side-effects, and cost. For example, asthma

Asthma

Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...

tics have been reported to have worsening symptoms when using beta blocker

Beta blocker

Beta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...

s. Most drugs have other uses; sometimes the presence of other symptoms can warrant the use of one particular antihypertensive (such as beta blockers in case of tremor

Tremor

A tremor is an involuntary, somewhat rhythmic, muscle contraction and relaxation involving to-and-fro movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, face, head, vocal folds, trunk, and legs. Most tremors occur in the...

 and nervousness

Anxiety

Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...

, and alpha blocker

Alpha blocker

Alpha-1 blockers constitute a variety of drugs which block α1-adrenergic receptors in arteries and smooth muscles.-Pharmacology:...

s in case of benign prostatic hyperplasia

Benign prostatic hyperplasia

Benign prostatic hyperplasia also known as benign prostatic hypertrophy , benign enlargement of the prostate , and adenofibromyomatous hyperplasia, refers to the increase in size of the prostate....

). The JNC 7 report outlines compelling reasons to choose one drug over the others for certain individual patients.

Non-drug treatment options

Several studies have found that hibiscus tea

Hibiscus tea

Hibiscus tea is the infusion made from the calyces of the Hibiscus sabdariffa flower, an herbal tea drink consumed both hot and cold by people around the world...

 has a substantial antihypertensive effect attributable to the flower's ACE-inhibiting anthocyanin content, and possibly to a diuretic effect. One study found that hibiscus conferred an antihypertensive effect comparable to 50 mg./day of the drug captopril.

Another potential treatment is Coenzyme Q10, which a meta analysis of 12 studies found reductions in systolic pressure of 10–17 points and a reduction in diastolic pressure of 8–10 points with doses of roughly 200 mg/day.