Anti-hypertensive medications are needed for the management of Stage 1 Hypertension and above which is not controlled by lifestyle modifications. For high blood pressure classified as prehypertension, currently only lifestyle modifications are recommended as treatment and anti-hypertensive drugs are not used. (Read blood pressure chart to know the types of blood pressure.)
Medications are started if a person either has systolic blood pressure ≥140 mm of Hg or has diastolic blood pressure ≥90 mm of Hg. An ACE-inhibitor is usually the first medication started in hypertension, and more drugs are added if the current regimen is not adequately controlling the blood pressure.
Anti-hypertensive drugs may be started even at lower blood pressure levels (prehypertension) if there are concurrent conditions that increase the overall risk of cardiovascular disease, for e.g. diabetes, chronic kidney disease, dyslipidemia, etc.
Most of the people with high blood pressure have no symptoms and feel perfectly healthy even though there blood pressure is elevated. However, bringing down the blood pressure in the desired range is of paramount importance because raised blood pressure slowly keeps damaging various organs throughout the body. Thus controlling the blood pressure, whether by lifestyle changes or anti-hypertensive drugs, is necessary to prevent the future complications of hypertension.
Compliance with the antihypertensive medications is an important issue for the management of hypertension. Since most of the people with high blood pressure are asymptomatic, many people don't take their medications seriously. They may forget taking pill or may not take all pills, or even stop medications on their own. This reduces the effectiveness of therapy and increases the risks of organ damage. So, even if one has no symptoms, he/she must take the high blood pressure medications with utmost sincerity.
The goal of management of hypertension is to achieve systolic blood pressure <135-140 mm of Hg and diastolic blood pressure <80-85 mm of Hg.
If a person has diabetes or chronic kidney disease or coronary heart disease (angina, etc.) or any other cardiovascular risk factor, then the target blood pressure is systolic <130 mm of Hg and diastolic <80 mm of Hg. Persons with daily loss of more than 1 g of protein in urine may require more aggressive therapy to achieve a systolic blood pressure <120 mm of Hg.
Failure to reduce the blood pressure below 140/90 mm of Hg despite taking three or more antihypertensive drugs (including a diuretic) is referred to as resistant hypertension.
Table 1: Anti-hypertensive Drugs for High Blood Pressure
Diuretics | Thiazide Diuretics - Hydrochlorothiazide, Chlorthalidone Loop Diuretics - Furosemide, Ethacrynic acid Potassium Sparing Diuretics - Amiloride, Triamterene Aldosterone-receptor blockers - Spironolactone, Eplerenone |
Beta-blockers | Propranolol, Metoprolol, Atenolol |
Combined alpha and beta blockers | Carvedilol, Labetalol |
ACE (Angiotensin-converting enzyme) inhibitors | Captopril, Lisinopril, Ramipril |
Angiotensin II Receptor Blockers (ARBs) | Losartan, Valsartan, Candesartan |
Calcium Channel Blockers | Nifedipine, Verapamil, Diltiazem |
Other Drugs | Alpha Blockers - Prazosin, Terazosin, Doxazosin Direct Vasodilators - Hydralazine, Minoxidol Renin Inhibitors - Aliskiren Centrally acting Sympatholytic Drugs - Clonidine, Methyldopa, Reserpine |
Diuretics are the drugs that increase the loss of fluid and water by the kidneys. This helps in lowering the blood pressure. There are many different subtypes of diuretics as mentioned in the table above.
Beta-blockers block the effects of certain chemicals on the heart muscle, resulting in slowing of heart rate and force of contraction of the heart.
Angiotensin is a hormone that plays a very important role in raising the blood pressure. ACE-inhibitors prevent the formation of this hormone where as ARBs block the effect of angiotensin on target tissues.
Calcium channel blockers reduce the blood pressure by blocking the entry of calcium into the muscles of the arterial wall. This relaxes the muscles and thus the artery wall, causing a fall in blood pressure.
There are numerous other medications with different mechanisms, but the above described ones are the most important ones used for the management of high blood pressure.
The choice of drugs varies with each individual depending upon age, severity of hypertension, ethnicity, presence of other concurrent disease conditions and presence of other risk factors for cardiovascular diseases. Cost, adverse effects and daily frequency of taking the doses are also secondarily considered. Usually a person with high blood pressure is started on single medication, and more drugs are added if the blood pressure is not adequately controlled.
These medicines only control the blood pressure; they don't cure it. Lifelong medications may be necessary in hypertensive people as blood pressure rises again if the medications are stopped. Moreover, the medications need to be taken without fail. Skipping doses or not taking enough medications will result in inadequate control of blood pressure. Finally, the main side effects of major anti-hypertensive medications are mentioned below.
Table 2: Most Important Adverse Effects of Anti-hypertensive Drugs
Diuretics | Thiazide Diuretics - Hydrochlorothiazide, Chlorthalidone
Loop Diuretics - Furosemide, Ethacrynic acid
Potassium Sparing Diuretics - Amiloride, Triamterene
Aldosterone-receptor blockers - Spironolactone, Eplerenone
|
Beta-blockers | Low Heart Rate, Tiredness, Bad Dreams, Muscle Weakness, Gastric Disturbances, Asthma like symptoms |
Combined alpha and beta blockers | Low Heart Rate, Tiredness, Bad Dreams, Muscle Weakness, Gastric Disturbances, Bronchospasm |
ACE (Angiotensin-converting enzyme) inhibitors | Cough, Postural Hypotension, Indigestion, Rashes, Diarrhea, Neuropathy |
Angiotensin II Receptor Antagonists | Low Blood Pressure, Drowsiness, Dizziness |
Calcium Channel Blockers | Palpitations, Constipation, Headache, Dizziness, Swelling in the Ankle region |
Other Drugs | Alpha Blockers - Prazosin, Terazosin, Doxazosin
Direct Vasodilators - Hydralazine, Minoxidol
Renin Inhibitors - Aliskiren
Clonidine
Methydopa
|
*The table lists only some of the major side effects. There can be numerous other rare side effects not mentioned here. All side effects are mentioned in the information booklet accompanying these drugs.