What are the Basic Drugs for treating Hypertension?

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Treatment of High Blood Pressure | Hypertension You should always Keep in mind that high blood pressure is usually present for many years before its complications develop. The idea, therefore, is to treat hypertension early, before it damages important organs in the body. Accordingly, increased public awareness and screening programs to detect early, uncomplicated hypertension are the keys to successful treatment of high blood pressure. By treating high blood pressure successfully early enough, you can significantly decrease the risk of stroke, heart attack, and kidney failure.

The goal for patients with combined systolic and diastolic hypertension is to attain a blood pressure of 140/85 mm Hg. Bringing the blood pressure down even lower, as mentioned earlier, may be desirable in African American patients, and patients with diabetes or chronic kidney disease. Although life style changes in pre-hypertensive patients is appropriate, it is not well established that treatment with medication of patients with pre-hypertension is beneficial.

Blood pressure that is persistently higher than 140/ 90 mm Hg usually is treated with lifestyle modifications and medication. If the diastolic pressure remains at a borderline level (usually under 90 mm Hg, yet persistently above 85), however, more aggressive treatment also may be started in certain circumstances. These circumstances include borderline diastolic pressures in association with end-organ damage, systolic hypertension, or factors that increase the risk of cardiovascular disease, such as age over 65 years, African American decent, smoking, hyperlipemia (elevated blood fats), or diabetes.

Any one of the several classes of medications may be started, except the alpha-blocker medications. The alpha-blockers drugs are used only in combination with another anti-hypertensive medication in specific medical situations.

In some particular situations, certain classes of anti-hypertensive drugs are preferable to others as the first line (choice) drugs. For example, Angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blocking (ARB) drugs are the drugs of choice in patients with heart failure, chronic kidney failure (in diabetics or non-diabetics), or heart attack (myocardial infarction) that weakens the heart muscle (systolic dysfunction), as these have remodeling effect on heart muscles. Also, beta-blockers are sometimes the preferred treatment in hypertensive patients with a resting tachycardia (racing heart beat when resting) or an acute (rapid onset, current) heart attack.

Treatment of High Blood Pressure | Hypertension

Furthermore, patients with hypertension may sometimes have a co-existing, second medical disease. In such cases, a particular class of anti-hypertensive medication or combination of drugs may be chosen as the first line (initial) approach. The idea in these cases is to control the hypertension while also benefiting the second condition. For example, beta-blockers may treat chronic anxiety or migraine headache as well as the hypertension. Also, the combination of an ACE inhibitor and an ARB drug can be used to treat certain diseases of the heart muscle (called cardiomyopathies) and certain kidney diseases where reduction in proteinuria would be beneficial.

In some other situations, certain classes of anti-hypertensive medications should not be used (are contraindicated). Dihydropyridine calcium channel blockers used alone may cause problems for patients with chronic renal disease by tending to increase proteinuria. However, an ACE inhibitor will decease this effect. Furthermore, the non-dihydropyridine type of calcium channel blockers(Verapamil, Dilteazam) should not be used in patients with heart failure or certain abnormal heart rates or rhythms (arrhythmias). On the other hand, these drugs may be beneficial in treating certain other arrhythmias. Also, some drugs, such as minoxidil, since it is so powerful, usually are reserved for  second or third line choices for treatment. Clonidine is an excellent drug but has side effects such as fatigue, sleepiness, and dry month that make it a second or third line choice. That is, it is used only after all of the first and second line drugs have been tried without success.

Most of the times, Doctors have to use combination therapy of Drugs. The use of combination drug therapy for hypertension is not uncommon. At times, using smaller amounts of one or more agents in combination can minimize side effects while maximizing the anti-hypertensive effect. For example, diuretics, which also can be used alone, are more often used in a low dose in combination with another class of anti-hypertensive medications. In this way, the diuretic has fewer side effects while it improves the blood pressure-lowering effect of the other drug. Diuretics also are added to other anti-hypertensive medications when a patient with hypertension also has fluid retention and swelling (edema).

The ACE inhibitors or angiotensin receptor blockers may be useful in combination with most other anti-hypertensive medications. ACE inhibitors and angiotensin receptor blockers ARBs  have additive effects in treating patients with cardiomyopathies and proteinuria. Another useful combination is that of a beta-blocker with an alpha-blocker in patients with high blood pressure and enlargement of the prostate gland in order to treat both conditions simultaneously. Caution is necessary, however, when combining two drugs that both lower the heart rate. For example, adding a beta-blocker to a non-dihydropyridine calcium channel blocker (e.g., diltiazem or verapamil) warrants caution. Patients receiving a combination of these two classes of drugs need to be monitored carefully to avoid an excessively slow heart rate (bradycardia). Combining alpha and beta-blockers may be beneficial for cardiomyopathies and hypertension. Carvedilol (Coreg) is useful for cardiomyopathies and labetalol for hypertension patients.

Treatment of High Blood Pressure | Hypertension In a hospital setting, injectable drugs may be used for the emergency treatment of hypertension. The most commonly used agents in this situation are sodium nitroprusside (Nipride, Isoket) and labetalol (Normodyne). As already mentioned, emergency medical therapy may be needed for patients with severe (malignant) hypertension. In addition, emergency treatment of hypertension may be necessary in patients with short duration (acute) congestive heart failure LVF, dissecting aneurysm (dilation or widening) of the aorta, stroke, and toxemia of pregnancy (see below). In emergency, sublingual medication with capotopril ACE inhibitor, or sublingual drops of Nefedipine are also used.

Women with hypertension may become pregnant. These patients have an increased risk of developing preeclampsia or eclampsia (toxemia) of pregnancy. These conditions usually develop during the last three months (trimester) of pregnancy. In preeclampsia, which can occur with or without pre-existing hypertension, affected women have 3 things, hypertension, protein loss in the urine (proteinuria), and swelling (edema). In eclampsia (toxemia), convulsions also occur and the hypertension may require prompt treatment. The foremost goal of treating the high blood pressure in toxemia is to keep the diastolic pressure below 105 mm Hg in order to prevent a brain hemorrhage in the mother.

Hypertension that develops before the 20th week of pregnancy almost always is due to pre-existing hypertension and not toxemia. High blood pressure that occurs only during pregnancy, called gestational hypertension, may start late in the pregnancy. These women, however, do not have proteinuria, edema, or convulsions. Furthermore, gestational hypertension appears to have no ill effects on the mother or the fetus. This form of hypertension resolves shortly after delivery, although it may recur with subsequent pregnancies.

The use of medications for hypertension during pregnancy is controversial. The key question is, "At what level should the blood pressure be maintained?" For one thing, the risk of untreated mild to moderate hypertension to the fetus or mother during the relatively brief period of pregnancy probably is not very large. Furthermore, lowering the blood pressure too much can interfere with the flow of blood to the placenta and thereby impair fetal growth. So, some sort of a compromise must be met. Accordingly, not all mild or moderate hypertension during pregnancy needs to be treated with medication. If it is treated, however, the blood pressure should be reduced slowly and not to very low levels, perhaps not below 140/80.

The anti-hypertensive agents used during pregnancy need to be safe for normal fetal development. The beta-blockers, hydralazine (an old vasodilator), labetalol, alpha methyldopa (Aldomet), and more recently, the calcium channel blockers have been advocated as suitable medications for hypertension during pregnancy. Certain other anti-hypertensive medications, however, are not recommended (they are contraindicated) during pregnancy. These include the ACE inhibitors, the ARB drugs, and probably the diuretics. ACE inhibitors may aggravate a diminished blood supply to the uterus (uterine ischemia) and cause kidney dysfunction in the fetus. The ARB drugs may even lead to death of the fetus. Diuretics can cause depletion of the blood volume and so impair placental blood flow and fetal growth

Angiotensin converting enzyme inhibitors (ACE Inhibitors) and angiotensin receptor blockers

Treatment of High Blood Pressure | Hypertension The angiotensin converting enzyme (ACE) inhibitors and the angiotensin receptor blocker (ARB) drugs both affect the renin-angiotensin hormonal system, which, as mentioned previously, helps regulate the blood pressure. The ACE inhibitors work by blocking (inhibiting) an enzyme that converts the inactive form of angiotensin in the blood to its active form. The active form of angiotensin constricts or narrows the arteries, but the inactive form cannot. With an ACE inhibitor as a single drug treatment (monotherapy), 50 to 60 percent of Caucasians usually achieve good blood pressure control. African American patients may also respond, but they require higher doses and frequently do best when an ACE inhibitor is combined with a diuretic. (Diuretics are discussed below.)

As an added benefit, ACE inhibitors may reduce an enlarged heart (left ventricular hypertrophy) in patients with hypertension. These drugs also appear to slow the deterioration of kidney function in patients with hypertension and protein in the urine (proteinuria). Moreover, they have been particularly useful in slowing the progression of kidney dysfunction in hypertensive patients with kidney disease resulting from Type 1 diabetes (insulin-dependent). Accordingly, ACE inhibitors usually are the first line drugs of choice to treat high blood pressure in cases that also involve congestive heart failure, chronic kidney failure in both diabetics and non-diabetics, and heart attack (myocardial infarction) that weakens the heart muscle (systolic dysfunction). ARB drugs are currently recommended for first line renal protection in diabetic nephropathy (kidney disease).

Patients who are treated with ACE inhibitors who also have kidney disease should be monitored for further deterioration in kidney function and high serum potassium. In fact, these drugs may be used to reduce the loss of potassium in people who are being treated with diuretics that tend to cause patients to lose potassium. ACE inhibitors have few side effects. One bothersome side effect, however, is a chronic cough. The ACE inhibitors include enalapril (Vasotec, Renitec, Zepres), captopril (Capoten), lisinopril (Zestril and Prinivil, Lame), benazepril (Lotensin), quinapril (Accupril), perindopril (Aceon), ramipril (Altace), trandolapril (Mavik), fosinopril (Monopril), and moexipril (Univasc ).

Usually we prefer Monopril for hypertension in kidney failure patients.

For patients who develop a chronic cough on an ACE inhibitor, an ARB drug is a good substitute. ARB drugs work by blocking the angiotensin receptor (binder) on the arteries to which activated angiotensin 11 must bind to have its effects. As a result, the angiotensin is not able to work on the artery. (angiotensin is a hormone that constricts the arteries.) The ARB drugs appear to have many of the same advantages as the ACE inhibitors but without the associated cough. Accordingly, they are also suitable as first line agents to treat hypertension. ARB drugs include losartan (Cozaar), irbesartan (Avapro), valsartan (Diovan), candesartan (Atacand), olmesartan (Benicar), telmisartan (Micardis), and eprosartan (Teveten).

In patients who have hypertension in addition to certain second diseases, a combination of an ACE inhibitor and an ARB drug may be effective in controlling the hypertension and also benefiting the second disease. For example, while treating hypertension, this combination of drugs can reduce the loss of protein in the urine (proteinuria) in certain kidney diseases and perhaps help strengthen the heart muscle in certain diseases of the heart muscle (cardiomyopathies). Note that both the ACE inhibitors and the ARB drugs are not to be used (are contraindicated) in pregnant women.

Beta-blockers

Treatment of High Blood Pressure | Hypertension The sympathetic nervous system is a part of the nervous system that helps to regulate certain involuntary (autonomic) functions in the body such as the function of the heart and blood vessels. The nerves of the sympathetic nervous system extend throughout the body and exert their effects by releasing chemicals that travel to nearby cells in the body, for example, muscle cells. The released chemicals bind to receptors (molecules) on the surface of the nearby cells and stimulate or inhibit the function of the cells. In the heart and blood vessels, the receptors for the sympathetic nervous system that are most important are the beta receptors. When stimulated, beta-receptors in the heart increase the heart rate and the strength of heart contractions (pumping action). Beta-blocking drugs acting on the heart on these Beta receptors, therefore, slow the heart rate and reduce the force of the heart’s contraction.

Stimulation of beta-receptors in the smooth muscle of the peripheral arteries and in the airways of the lung causes these muscles to relax. Accordingly, beta-blockers cause contraction of the smooth muscle of the peripheral arteries and thereby decrease the blood flow to the tissues throughout the body. As a result, the patient may experience, for example, coolness in the hands and feet. Likewise, in response to the beta-blockers, the airways are squeezed (constricted) by the contracting smooth muscle. This squeezing (impingement) on the airway causes wheezing, especially in individuals with a tendency for asthma. So remember, Beta Blockers are contracindicated in Asthametic patients. In short, beta-blockers reduce both the force of the heart's pumping action and the blood pressure that the heart generates in the arteries.

Beta-blockers remain useful medications in treating hypertension, especially in patients with a fast heartbeat while resting (tachycardia), cardiac chest pain (angina), or a recent heart attack (myocardial infarction). For example, beta-blockers appear to improve long-term survival when given to patients who have had a heart attack. Whether beta-blockers can prevent heart problems (are cardio-protective) in patients with hypertension any more than other anti-hypertensive medications, however, is uncertain. Beta-blockers may be considered for treatment of hypertension because they also may treat co-existing medical problems. For example, beta-blockers can help treat chronic anxiety or migraine headaches in people with hypertension. The common side effects of these drugs include depression, fatigue, nightmares, sexual impotence in males, and increased wheezing in people with asthma. The beta-blockers include atenolol (Tenormin), propranolol (Inderal), metoprolol (Toprol, Mepressor, Merol), nadolol (Corgard), betaxolol (Kerlone), acebutolol (Sectral), pindolol (Visken), and bisoprolol (Zebeta).

Diuretics

Treatment of High Blood Pressure | Hypertension Diuretics are among the oldest known medications for treating hypertension. They work in the tiny tubes (tubules) of the kidneys to remove salt from the body. Water (fluid) also may be removed along with the salt. Diuretics may be used as single drug treatment (monotherapy) for hypertension. More frequently, however, low doses of diuretics are used in combination with other anti-hypertensive medications to enhance the effect of the other medications.

The diuretic hydrochlorothiazide (Hydrodiuril) works in the far end (distal) part of the kidney tubules to increase the amount of salt that is removed from the body in the urine. In a low dose of 12.5 to 25 mg per day, this diuretic may improve the blood pressure-lowering effects of other anti-hypertensive drugs. The idea is to treat the hypertension without causing the adverse effects that are sometimes seen with the higher doses of hydrochlorothiazide. There side effects include potassium depletion and elevated levels of triglyceride (fat), uric acid, and glucose (sugar) in the blood.

Occasionally, when salt retention causing accumulation of water and swelling (edema) is a major problem, the more potent, so-called, loop diuretics may be used in combination with other anti-hypertensive medications. (The loop diuretics are so called because they work in the loop segment of the kidney tubules to eliminate salt.) The most commonly used diuretics to treat hypertension include hydrochlorothiazide (Hydrodiuril, Diuza), the loop diuretics furosemide (Lasix) and torsemide (Demadex), the combination of triamterene and hydrochlorothiazide (Dyazide), and metolazone (Zaroxolyn). For those individuals who are allergic to sulfa drugs, ethacrynic acid, a loop diuretic, is a good option. Note that diuretics probably should not be used in pregnant women.

Calcium channel blockers (CCBs)

Calcium channel blockers inhibit the movement of calcium into the muscle cells of the heart and arteries. The calcium is needed for these muscles to contract. These drugs, therefore, lower blood pressure by decreasing the force of the heart's pumping action (cardiac contraction) and relaxing the muscle cells in the walls of the arteries.

Three major types of calcium channel blockers are used. One type is the dihydropyridines, which do not slow the heart rate or cause other abnormal heart rates or rhythms (cardiac arrhythmias). These drugs include amlodipine (Norvasc), sustained release nifedipine (Procardia XL, Adalat CC, Adalet retard), felodipine (Plendil), and nisoldipine (Sular).

The other two types of calcium channel blockers are referred to as the non-dihydropyridine agents. One type is verapamil (Calan, Covera, Isoptin, Verelan) and the other is diltiazem (Cardizem, Tiazac, Dilacor, and Diltia). Both the dihydropyridines and the non-dihydropyridines are very useful when used alone or in combination with other anti-hypertensive agents. The non-dihydropyridines, however, are not recommended (contraindicated) in congestive heart failure or with certain arrhythmias. Sometimes, however, these same dihydropyridines are useful in preventing certain other arrhythmias.

Many of the calcium channel blockers come in a short-acting form and a long-acting (sustained release) form. The short-acting forms of the calcium channel blockers, however, may have adverse long-term consequences, such as strokes or heart attacks. These effects are presumably due to the wide fluctuations in the blood pressure and heart rate that occur during treatment. The fluctuations result from the rapid onset and short duration of the short-acting compounds. When the calcium channel blockers are used in sustained release preparations, however, less fluctuation occurs. Accordingly, the sustained release forms of calcium channel blockers are probably safer for long-term use. The main side effects of these drugs include constipation, swelling (edema), and a slow heart rate (only with the non-dihydropyridine types).

Alpha-blockers

Treatment of High Blood Pressure | Hypertension Alpha-blockers lower blood pressure by blocking alpha-receptors in the smooth muscle of peripheral arteries throughout the tissues of the body. The alpha-receptors are part of the sympathetic nervous system, as are the beta-receptors. The alpha-receptors, however, serve to narrow (constrict) the peripheral arteries. Accordingly, the alpha-blockers cause the peripheral arteries to widen (dilate) and thereby lower the blood pressure.

Recent evidence, however, suggests that using alpha-blockers alone as a first line drug choice for hypertension may actually increase the risk of heart-related problems, such as heart attacks or strokes. Alpha-blockers, therefore, should not be used as an initial drug choice for the treatment of high blood pressure. Examples of alpha-blockers include terazosin (Hytrin) and doxazosin (Cardura) .

Alpha-blockers are particularly useful in patients with enlargement of the prostate gland (which usually occurs in older men) because these drugs reduce the problems associated with urinating. Alpha-blockers alone, however, have a relatively small blood pressure-lowering effect. Accordingly, when hypertension coexists with prostatic enlargement, another anti-hypertensive medication should be used together with an alpha-blocker. For example, tamsulosin (Flomax) or alfuzosin (Uroxatral) are alpha-blockers that work well in combination with other anti-hypertensive medications.

Clonidine

Clonidine (Catapres) is an antihypertensive drug that works centrally. That is, it works in a control center for the sympathetic nervous system in the brain. The drug is referred to as a central alpha agonist because it stimulates alpha-receptors in the brain. The result of this central stimulation, however, is to decrease the sympathetic nervous system outflow and to decrease the stiffness (resistance) of the peripheral arteries. Clonidine lowers the blood pressure, therefore, by relaxing (dilating or widening) the peripheral arteries throughout the body. This drug is useful as a second or third line drug choice for lowering blood pressure when other anti-hypertensive medications have failed. It also may be useful on an as-needed basis to control or smooth out fluctuations in the blood pressure. This drug tends to cause dryness of the mouth and fatigue so that some patients do not tolerate it. Clonidine comes in an oral form or as a sustained release skin patch.

Minoxidil

Treatment of High Blood Pressure | Hypertension Minoxidil is the most potent of the drugs that lower blood pressure by dilating the peripheral arteries. This drug, however, does not work through the peripheral sympathetic nervous system, as do the alpha and beta-blocker drugs, or through the control center in the brain, as does clonidine. Rather, it is a muscle relaxant that works directly on the smooth muscle of the peripheral arteries throughout the body. Minoxidil is used for patients who have not responded to any other medications. It must be combined with a beta-blocker or clonidine to prevent an increase in the heart rate and with a diuretic to prevent retention of fluid (swelling). Minoxidil may also increase hair growth. So Minoxidil is also used for baldness.

When uncomplicated hypertension has not caused symptoms, as often happens, some patients tend to forget about their medications. Patients also tend to fail to take their medications as prescribed (non-compliance or non-adherence) if they are causing side effects. Remember that quality of life issues are very important, especially with regard to compliance with prescribed blood pressure medications. Thus, certain anti-hypertensive medications may cause such side effects as fatigue and sexual impotence. These side effects understandably can have profound effects on the patient's quality of life and compliance with treatment. Likewise, more resistant cases of hypertension that require more medication may cause more adverse effects, and, therefore, less compliance.

In dosing schedules that require taking medication 2 to 4 times a day (split dose), some patients will remember to take their medicine only some of the times. In contrast, medications that can be given once daily tend to be remembered more regularly.

Expensive blood pressure medications, especially if insurance does not cover the costs, may also reduce compliance. The reason for this is that people attempt to save money by skipping doses of the prescribed medication. Remember that the least expensive medication regimes use generic (not brand name) drugs, such as are readily available for some of the diuretics and beta-blockers. Reduced costs of medication may also be achieved by lifestyle changes such as losing weight, reducing dietary sodium, decreasing consumption of alcohol, and exercising regularly. If these changes in lifestyle are effective, the patient may require less medication. For further information, please read the natural treatment of hypertension.

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