Hypertension, commonly called high blood pressure, is a disease that affects about 1 in 3 people in the world. Hypertension is a chronic disease with no cure and the vast majority of cases, but currently has a large arsenal of drugs for its control.
We know that reducing blood pressure to below 140/90 mmHg are associated with a lower rate of complications and greater long-term survival. Therefore, this is the treatment target.
Treatment of hypertension is usually based on two strategies: lifestyle changes and drug therapy. In this article we will only address the drug treatment, describing the indications and side effects of the main anti-hypertensive drugs available in the market.
There are dozens of different drugs approved for the control of blood pressure levels. Recent studies have shown that the most important in the treatment of hypertension and how it can reduce blood pressure, and not necessarily the type of drug used.
Currently, three classes of antihypertensive drugs are considered first line by presenting good response in controlling blood pressure and low incidence of serious adverse effects: diuretics, ACE inhibitors (or ARBs 2) inhibitors and calcium channel. We'll talk about these and other following drugs.
There is no problem in the association of more than one antihypertensive drug. Some patients with severe hypertension need 3, 4 or even 5 drugs to control your blood pressure. The monotherapy treatment, with only one drug is often used only in milder cases, those which, without treatment, have their blood pressure below 160/90 mmHg. Patients with higher pressures, especially to above 170/90 mmHg, can hardly bring the values below 140/90 mmHg with a single drug.
Most commercially available antihypertensive drugs consists of many years of clinical use and a good safety profile. However, like any drug, there is always the risk of side effects. The most common adverse effect of all classes is hypotension. This problem can be avoided with careful control of drug doses, especially at the beginning of treatment. Sexual impotence is another problem that can occur, but is usually more common in elderly patients who already have other risk factors for erectile dysfunction.
In general, though indicated, antihypertensives are well tolerated and effective drugs.
Now, let's summarize the main antihypertensive groups and their main drug.
Diuretics are drugs used for decades in the treatment of hypertension, is today considered one of the best options for the control of blood pressure levels. Diuretics can be used as monotherapy or as part of a multiple antihypertensive therapy with more than one drug to different classes.
In general, unless contraindications and special cases, it is suggested that the diuretic is the first or a maximum of the second drug of any antihypertensive regimen. The Hypertensive patients treated with 2 or 3 drugs, none of which a diuretic, probably with an antihypertensive regimen poorly chosen.
There are three major groups of diuretics that can be used to treat hypertension:
a. Thiazide diuretics
The thiazide diuretics are the category most indicated for the treatment of hypertension. Are inexpensive drugs with good results, especially for the black population, the elderly and diabetics.
Thiazide diuretics most commonly used in medical practice are:
Hydrochlorothiazide (recommended dose between 12.5 and 25 mg per day once daily).
Chlorthalidone (recommended dose between 12.5 and 25 mg per day once daily).
Indapamide (recommended dose between 1.25 and 2.5 mg daily in a single daily dose).
Metolazone (recommended dose between 2.5 and 5 mg per day in a single daily dose).
The most recent studies have pointed to a better performance of chlorthalidone in reducing long-term cardiovascular events and mortality. The likely cause is its long duration of action (over 24 hours), which can be more than twice the hydrochlorothiazide. However, as already mentioned, as long as the pressure can be controlled, any of the four drugs in this class is an excellent choice.
Excepting metolazone in patients with advanced renal insufficiency (creatinine clearance below 30 ml / min) thiazides are not effective drugs, and should not be the diuretic of choice for blood pressure control in these patients.
Among the most common side effects of thiazides are the worsening of glucose levels in diabetics (this effect usually occurs only in high doses), increased uric acid levels, hypokalemia (low blood potassium), hyponatremia (low blood sodium) and dehydration.
b. Loop diuretics
Loop diuretics are more potent diuretics, but its action time is much shorter. In practice, loop diuretics are less effective in controlling blood pressure thiazides, these should not be the first treatment option for most patients.
Exceptions are patients with advanced chronic renal failure or heart failure requiring control of edemas. In such cases, loop diuretics are the most suitable.
There are more than one type of loop diuretic, but in practice, the most used drug is furosemide, well known by the trade name Lasix.
Furosemide is commonly used in the treatment of hypertension in doses of 20 to 80mg per day in a single dose or in two daily doses separated by 6 hours of interval (for example, 1 tablet at 9 hours 1 tablet to 15 hours). Not shown with the prescription of furosemide at 12 hour intervals between doses. much higher doses than 80 mg can be used in patients with severe edema frames.
The main side effects of furosemide are similar to the thiazide diuretics.
c. Potassium sparing diuretics
Potassium-sparing diuretics are diuretics weak and is not indicated for the treatment of many cases of hypertension. They, however, can be used as a supplementary drug in resistant cases of hypertension or in patients with heart failure, whether the patient has to make use of a thiazide diuretic or a loop.
In medical practice, the most widely used diuretic potassium-sparing is spironolactone, also known by its trade name Aldactone. The usual dose of spironolactone for hypertension is 25 mg to 50 mg per day in a single daily dose.
Among the side effects, the most dangerous is hyperkalemia (excess blood potassium), which can lead to serious cardiac arrhythmias.
Inhibitors of angiotensin converting enzyme, better known by the acronym ACE inhibitors are an antihypertensive class used very successfully for over 30 years.
As the diuretic, ACE inhibitors are drugs that can be used as monotherapy or as part of a multiple drug treatment. Unless contraindications, ACE inhibitors may be used on any type of patient, but they should be treated as preferred drug for treatment of hypertension in subjects with the following characteristics:
Diabetics
Patients with left ventricular hypertrophy
Patients with heart failure
Patients who have suffered a myocardial infarction
Patients with proteinuria
Patients with chronic renal failure
In general, ACE inhibitors have anti-hypertensive action more intense in white and young people, being less effective in blacks and elderly. This does not mean, however, that it can not use ACE inhibitors in this group, especially if the patient has one or more of the six characteristics listed above.
ACE inhibitors are a group largely explored by the pharmaceutical industry, there currently on the market, several different drugs in this family. In general, any ACEI shows clear superiority over the other.
ACE inhibitors most commonly used in the medical practice are:
Benazepril (recommended dose of 10 to 40 mg daily, once daily)
Captopril (recommended dosage between 25 to 150 mg per day divided in 2 or 3 taken per day)
Cilazapril (recommended dose of 0, 5 to 2.5 mg per day as a single daily dose)
Enalapril (recommended dose from 5 to 40 mg per day, once daily or 2 times per day)
Lisinopril (recommended dose between 5 and 40 mg day, in a single daily dose)
Perindopril (recommended dosage between 2 to 16 mg per day, in a single daily dose)
Ramipril (recommended dose between 2.5 to 20 mg per day, once daily or 2 times per day)
Captopril is the oldest drug in this list. By having a shorter action time, its dosage is less comfortable, and need to take it up to 3 times a day. Therefore, its use has now been restricted to the timely treatment of blood pressure peaks in patients already treated with other drugs.
The combination of ACE inhibitors with potassium-sparing diuretics should be made with caution, because both are drugs that may increase potassium levels in the blood.
The most troublesome side effect of ACE inhibitors is a cough that may arise at any time during treatment and only disappear with the discontinuation of the drug.
Angiotensin II receptor antagonists receptor blockers (ARB)
Angiotensin II receptor antagonists, known by the acronym ARB, is an antihypertensive class of relatively new, but the mechanism of action similar to ACE inhibitors.
As the effects, efficacy and indications are the same as the ACE inhibitors, the choice between an ACE inhibitor or ARB is by individual preference account of the doctor or the patient. Price, dosage and colateiras effect profile are usually the factors taken into account when choosing between an ACE inhibitor or ARB.
The ARB most widely used in clinical practice are:
Candesartan (recommended dose of 16 to 32 mg daily, once daily)
Irbesartan (recommended dosage between 75 to 300 mg per day, in a single daily dose)
Losartan (recommended dosage between 50 to 100 mg per day, once daily)
Olmesartan (recommended dose 20 to 40 mg per day, once daily)
Telmisartan (recommended dose of 20-80 mg per day, once daily)
Valsartan (recommended dose 80 to 320 mg per day, once daily)
There are no studies to prove the superiority of one drug over another among those cited above. Again, the choice is individual.
Like ACE inhibitors, ARA II can also cause increased blood potassium. The great advantage of ARBs over the ACE inhibitor is the low occurrence of cough.
The combination of an ACE inhibitor and ARB was given up for some time for the treatment of heart failure and kidney disease with proteinuria. This statement, however, has fallen to the ground in recent years due to the high rate of side effects and cardiovascular events that recent studies have shown.
Calcium channel inhibitors are drugs also been used for many years in the treatment of hypertension. They are remedies that can even be used as monotherapy, but are usually prescribed to help control blood pressure in patients already treated with ACE inhibitors (or ARBs) and / or diuretic. The combination of an inhibitor of calcium channel with a diuretic is usually very effective in controlling hypertension in black patients or elderly.
The calcium channel inhibitors in clinical practice most widely used are:
Nifedipine Retard (better known as Adalat retard) (recommended dose of 30-120 mg per day, once daily)
Amlodipine (recommended dose between 2.5 to 10 mg per day, once daily)
Lercanidipine (recommended dose between 10 and 20 mg daily, a single daily dose)
felodipine (recommended dose between 2.5 and 20 mg daily, a single daily dose)
Calcium channel inhibitors are strong antihypertensive and should be started cautiously in elderly patients because of the risk of hypotension. These patients should start with the lowest dose and the same increased gradually every 15 days until adequate control of blood pressure.
The most common side effect of calcium channel inhibitors is edema (swelling) in the feet and legs, especially in patients with varicose veins and signs of venous insufficiency of the lower limbs.
Beta-blockers are drugs used to treat high blood pressure for many years. Since 2010, however, its use as first-line drug is not indicated.
Do not use beta-blockers as monotherapy, and drugs such as diuretics, ACE inhibitors, ARBs or calcium channel inhibitors, should have preference when choosing the composition of antihypertensive treatment.
However, in some clinical situations, the use of beta-blockers to control blood pressure may exhibit beneficial effects such as:
If the patient does not show any of the clinical conditions described above, the beta-blocker should be seen only as 3rd or 4th drug option for the control of hypertension.
Beta-blockers most commonly used in clinical practice are:
Atenolol (recommended dose of 25 to 100 mg per day, once daily)
Bisoprolol (recommended dose between 2.5 and 20 mg daily, once daily)
Carvedilol (recommended dose between 12.5 to 50 mg per day, divided into 2 intakes per day)
Metoprolol (recommended dosage between 50 to 450 mg per day divided in 2 or 3 taken per day)
Nebivolol (recommended dose between 5 to 40 mg per day in single daily dose)
Propranolol (recommended dose of 40 to 160 mg per day, divided into 2 intakes per day)
Beta-blockers should not be used in patients with asthma or those with baseline heart rate below 60 bpm.
The direct vasodilator, hydralazine and minoxidil represented by drugs, these drugs should only be used in the treatment of hypertensions difficult to control.
Hydralazine is most often used to minoxidil in that the lighter side effect profile. In general, it indicates the use of hydralazine in patients treated with at least one diuretic, an ACE inhibitor (or AIIRAs) and a calcium channel blocker, without further appropriate anti-hypertensive control. The dose of the hydralazine is 25 to 100 mg divided into 2 daily doses.
Among the most common side effects of hydralazine are fluid retention, tachycardia (rapid heart) and headache. Concomitant use of a diuretic and a beta-blocker alleviates side effects.
The only situation that the use of hydralazine can be considered as the first option is the case of pregnant women with severe hypertension. Like most anti-hypertensive drugs can not be used in pregnant women, hydralazine ends up being one of the few options available.
Minoxidil is a very powerful drug and is usually reserved for those cases of severe hypertension that do not give any type of antihypertensive combination. They are usually cases of patients already treated with 4 or 5 antihypertensive drugs that still maintain blood pressure levels above 200/100 mmHg. Minoxidil has many side effects, the most important growth by the body (hirsutism) and fluid retention.
Many doctors reserve the minoxidil as a last alternative drug treatment of hypertension. Its great advantage is the fact that it is extremely efficient, managing to control blood pressure as any other antihypertensive.
The alpha-1 blockers are drugs that have been less and less used in the treatment of hypertension. Studies have shown that this group is less effective, and has more adverse effects than first-line drugs.
Currently only indicates the use of alpha-1 blockers to control blood pressure in elderly men also present benign prostatic hypertrophy because these drugs act by reducing the size of the prostate. In these cases, it is a good choice to be the 3rd or 4th drug antihypertensive regimen.
The alpha-1 blockers most commonly used in clinical practice are:
Doxazosin (recommended dose from 1 to 16 mg per day, in a single daily dose)
Prazosin (recommended dosage between 2 to 20 mg per day, divided into 2 or 3 taken per day)
Terazosin (recommended dose from 1 to 20 mg per day, divided into 1 or 2 intakes per day)
Alpha agonists 2 adrenergic drugs are also used only in cases of difficult to control hypertension. Must be the 4th or 5th treatment option.
They are powerful antihypertensives, but its side effects are common, including drowsiness, dry mouth, headache and dizziness. Another problem of the alpha-2-agonists is the so-called rebound effect, characterized by a sudden rise in blood pressure when these drugs are discontinued.
The drugs most used of this class are:
Clonidine (recommended dose from 0.1 to 0.8 mg per day, divided into 2 intakes per day)
Methyldopa (recommended dose from 250 to 1000 mg per day, divided into 2 intakes per day)
Rilmenidine (dose Suggested between 1 and 2 mg daily, once daily)
