What Is Essential Hypertension?
High blood pressure is also known as hypertension. In almost 95% of affected patients, the cause of the blood pressure elevation is unknown and is a condition called primary or essential hypertension.
When Is It Time To Start Taking Blood Pressure Medication?
When lifestyle modifications fail to lower blood pressure to less than 140/90 mmHg in my patients, I recommend starting a medication to control hypertension. Even though I know that lowering blood pressure can help reduce the chance of having a heart attack or stroke, it is sometimes difficult for my patients to accept that they need to take a pill for the rest of their lives. Therefore, before I write that first prescription, I choose the medication that will lower blood pressure with the fewest possible side effects and least amount of intrusion in their lives.
In general, I prefer to prescribe a medication that can be taken once a day. In this case, I find that it is a good idea to take your pill at the same time every day, such as when you brush your teeth in the morning. That way you'll be less likely to miss a dose. If you do forget to take a pill every now and then, don't worry — it happens to most of us. It is unlikely that your blood pressure will rise as a result. Don't try to make up for the missed dose by taking extra medication the next day. This will only increase your chance of having side effects, some of which may be quite serious.
What Are The Different Types Of Blood Pressure Medications?
There are probably close to 100 different types of medicines currently available to treat high blood pressure, and new ones are being approved every year. These medicines belong to several different classes of drugs. The most commonly prescribed classes of drugs include diuretics (also known as "water pills"), beta-blockers, calcium channel blockers, ACE inhibitors, angiotensin receptor antagonists and vasodilators. In addition there are several "second-line" drugs that your physician may prescribe that don't exactly fit into these categories, but are still effective in treating high blood pressure. All of the medications mentioned in this article represent the generic forms, not the trademark brands, of blood pressure lowering agents.
Diuretics
Diuretics help lower blood pressure by removing extra salt and water from the body. They get their nickname, "water pills", from the fact that they make people urinate frequently, although this effect is less pronounced over time. These medicines, which include generic names such as hydrochlorothiazide, furosemide and spironolactone, have been used for years as a first choice for treating high blood pressure. They are effective, well tolerated and inexpensive.
I prescribe diuretics frequently for my patients who suffer from congestive heart failure since these patients often develop edema, which is also known as extra water or fluid accumulation, in their legs and lungs. I sometimes prescribe a small dose of a diuretic along with an ACE inhibitor or calcium channel blocker to help remove the extra water that may accumulate with these medicines. I avoid using certain diuretics in patients who suffer from gout because they can cause it to flare up unexpectedly. If you are taking a diuretic, your doctor or nurse practitioner may want you to have a blood test every once in a while. That's because diuretics remove potassium from the body along with extra salt and water. Eating foods rich in potassium, like bananas, is a good idea, but if your potassium level is low you may also need to take a potassium supplement.
Beta-blockers
Beta-blockers are commonly prescribed as a "first line" therapy for high blood pressure, and include generic names such as atenolol, metoprolol and propranolol. They work by blocking the sympathetic nervous system. This is the part of the body that is responsible for the "flight or fight" reflex. They also block the release of a protein called renin that causes blood vessels to narrow and, subsequently, raise blood pressure. These drugs also slow down your heart rate and can make you feel dizzy if you stand up too quickly. It's a good idea if you take a beta-blocker to sit on the edge of the bed for a minute or so before standing up and to remain standing for another minute before walking. If you begin to feel dizzy, sit back down and wait a few minutes before trying again.
As a cardiologist, I prescribe beta-blockers almost every day because they are effective in reducing chest pain and have been proven to help prevent the reoccurrence of a heart attack. They are powerful medicines, and are not for everyone. I avoid using them in patients with asthma because they can worsen the condition by causing narrowing of the airways of the lungs. I also avoid using this class of drug in patients who have clinically significant disease of the electrical system of the heart, so called "complete or advanced heart block", unless they have a pacemaker. This is due to the fact that beta-blockers not only slow down the heart rate, but also can cause delays in the electrical conduction system of the heart. When I prescribe beta-blockers for my diabetic patients, I caution them that beta-blockers can sometimes remove the "warning system" that tells them that their sugar is too low. If you are a diabetic and taking a beta-blocker you will need to pay careful attention to your blood sugar levels, and may have to adjust your insulin to prevent your sugar from going too low.
Some of my patients tell me that they don't feel well after taking a beta-blocker. They may have a hard time describing exactly what they feel, but know that they just don't feel right. Beta-blockers can cause people to feel tired, and have been known to cause depression. They may also contribute to erectile dysfunction in men, a condition commonly known as impotence. If you experience any of these side effects, or just don't feel well while taking a beta-blocker, please discuss this with your healthcare provider.
Calcium Channel Blockers
Calcium channel blockers lower blood pressure through a combination of effects on the heart, kidney and blood vessels. Some, like verapamil, predominately slow down the heart rate while others, like nifedipine or amlodipine, cause blood vessels to dilate or get bigger. Diltiazem does a bit of both. All calcium channel blockers help the kidney remove extra salt and water from the body, and thereby lower blood pressure. In addition to lowering blood pressure, calcium channel blockers are useful in preventing chest pain and slowing dangerously fast heart rhythms.
Calcium channel blockers remain some of the most commonly prescribed medications for the treatment of high blood pressure. In part, this is because they have few side effects. If you are taking a calcium channel blocker you might experience occasional constipation or develop slightly swollen ankles. The addition of a low dose of a diuretic can usually remove this extra fluid. The side effect I'm often worried about is bradycardia, or a slow heart-beat, which can occur in patients taking verapamil or diltiazem. By checking their pulse or recording their electrocardiogram, I ensure that my patients' heart rate is fast enough to safely continue taking these drugs.
ACE Inhibitors
The word "ACE" stands for angiotensin converting enzyme. ACE inhibitors block the enzyme that is responsible for creating angiotensin II, a protein that causes blood vessels to narrow and subsequently raise blood pressure. They also prevent the release of aldosterone, a protein that is created in the adrenal glands and forces the kidneys to retain extra salt and water. The ability of an ACE inhibitor to lower blood pressure can be enhanced by limiting the amount of salt in your diet or by taking a small dose of a water pill. Some of the more commonly prescribed generic ACE inhibitors are captopril, enalapril and lisinopril.
I use ACE inhibitors frequently in my practice because they have several beneficial effects for patients with heart disease. For example, ACE inhibitors have been proven to help people with congestive heart failure live longer. They are particularly effective for patients with "ventricular hypertrophy" or a thickened heart muscle, and they can slow the development of kidney failure in patients with diabetes. A recent study showed that ACE inhibitors can help prevent heart attacks and death in patients with coronary artery disease. I avoid prescribing ACE inhibitors to young women who are pregnant because these medications have been known to cause birth defects.
If you are taking an ACE inhibitor you have probably had several blood tests to make sure that your potassium level doesn't get too high, and to make sure that your kidneys are not being harmed. It is estimated that about ten percent of patients who take an ACE inhibitor develop a cough. This is not a dangerous side effect, but can be quite troubling. Fortunately, the cough goes away when you stop taking the medicine. A rare side effect, but one that is potentially life threatening, is the development of angioedema. This is a condition in which the tongue and lips begin to swell. Sometimes they swell so much that they can make breathing difficult. If this happens to you, go to the hospital immediately.
Angiotensin Receptor Antagonists
These are a new class of medicines that are similar to ACE inhibitors. In fact, many physicians prescribe them for their patients who developed a cough while taking and ACE inhibitor. These drugs, which include the generic losartan, valsartan and candesartan, work by preventing angiotensin II from attaching itself to the blood vessels. Since it can't get to the blood vessels, angiotensin II is unable to cause them to narrow and as a result the blood pressure falls. So far, these drugs appear to have few side effects. Even though they won't cause you to cough, they could raise the level of potassium in your blood and could temporarily hurt the kidneys. For these reasons, you may still need to have your blood checked on a periodic basis, just as you would if were you taking an ACE inhibitor.
Vasodilators
These drugs are rarely used alone and are usually reserved for those patients who require several medicines to lower blood pressure. They work through different mechanisms, but in the end they all lower blood pressure by causing blood vessels to dilate, or get bigger. Examples from this class include clonidine, prazosin, hydralazine, minoxidil and methyldopa. The most commonly seen side effect with these drugs is lightheadedness, but other side effects include dry mouth (clonidine), headache (hydralazine), excess body hair (minoxidil) and liver damage (methyldopa).
Which Medicine Is Right For Me?
Only your doctor or nurse practitioner can decide which is the best medicine for you. Because there are so many different types of blood pressure medicines available today, chances are that you and your healthcare provider will be able to find a medicine or combination of medicines that will lower your blood pressure effectively with the fewest possible side effects.
When deciding which drug to choose first, I rely on my previous experience and the recommendations set forth by the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. This committee meets every several years and publishes a report that makes recommendations based on the best available data from clinical trials. In otherwise healthy people, the Committee recommends starting a diuretic or a beta-blocker as the first choice for treating high blood pressure.
When other medical conditions exist, the initial agent should be individualized to the patient. For example, I prefer to prescribe an ACE inhibitor first for patients with congestive heart failure or an enlarged heart because it reduces mortality in these settings. I also prescribe ACE inhibitors for my diabetic patients because they help slow the development of kidney failure. For my patients who have suffered a heart attack, I'll prescribe a beta-blocker first because it helps to prevent chest pain and reduces the chance of having a second heart attack.
I also consider the ethnic background of my patients before choosing an agent. For example, I know that African Americans are more likely to respond to diuretics and calcium channel blockers whereas Caucasians usually have better initial results with beta-blockers and ACE inhibitors.
What If My Blood Pressure Is Still High After Taking Medication?
Don't be alarmed if you have been taking your medicine and your blood pressure remains elevated. You are not alone. It is estimated that only about 40% of patients will be able to lower their blood pressure to the desired level while taking a single drug. This means that more than half of patients will need to take two or more agents. Before I decide to start adding medications I try some simple things first. Sometimes increasing the dose will have the desired effect; other times it may be necessary to switch to a new class of drugs. When these maneuvers fail, I recommend that my patients follow a low salt diet and limit the amount of alcohol that they drink. I also take an inventory of all their medicines, including over-the-counter medicines, because certain drugs, like ibuprofen, reduce the effectiveness of blood pressure medicines. Most importantly, I reassure my patients that we will eventually find a combination that is safe and effective, and encourage them to let me know about any side effects. With their participation, we will succeed in controlling their high blood pressure.
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