Facts on File Encyclopedia of Health and Medicine

helpful and harmful is exceedingly thin. These
drugs have the potential to create life-threatening
arrhythmias. Other cardiovascular medications
may cause symptoms such as COUGH, HEADACHE,
ERECTILE DYSFUNCTION, tiredness, CONSTIPATION, dizzi-
ness, flushing, and edema (swelling, particularly
of the ankles and wrists). It is important for people
to know what side effects are possible with they
medications they are taking and to notify the doc-
tor if any of them occur. Though some side effects
are common to all of the drugs within a classifica-
tion, sometimes switching to a different medica-
tion within the same classification eliminates the
troublesome side effect.

ACE Inhibitors

Angiotensin-converting enzyme (ACE) inhibitors
block the action of angiotensin-converting
enzyme (ACE). Angiotensin II is a potent vasocon-
strictor that raises blood pressure. Blocking the
conversion of its precursor, angiotensin I
(angiotensinogen), prevents these events and low-
ers blood pressure. ACE inhibitors also have a
mild to moderate diuretic effect, further lowering
blood pressure by reducing blood volume.

Pregnant women should not take ACE

inhibitors during the second and third

trimesters of PREGNANCY, as these drugs

may cause harm or death to the fetus.

Doctors prescribe ACE inhibitors as first-line
treatment, usually in combination with diuretics,
to treat hypertension and heart failure and to
reduce the risk of subsequent heart attacks after
an initial heart attack. Some ACE inhibitor prod-
ucts combine an ACE inhibitor with a diuretic.

COMMON ACE INHIBITORS
benazepril (Lotensin) captopril (Capoten)
enalapril (Vasotec) fosinopril (Monopril)
lisinopril (Prinivil, Zestril) moexipril (Univasc)
perindopril (Aceon) quinapril (Accupril
ramipril (Aceon (Altace) trandolapril (Mavik)

Among the common side effects are HEADACHE,
gastrointestinal upset, dizziness, SKIN RASHor skin
sensitivity to sunlight, and fatigue. ACE inhibitors
have a propensity to cause a dry, nonproductive

cough; though annoying, the cough is benign and

typically goes away within two months of stop-

ping the medication.

Adenosine

Adenosine is an intravenously administered med-

ication that momentarily interrupts the flow of

the heart’s electrical pacing signals, creating an

“electrical short” of sorts that very briefly stops the

heart. It is a treatment for PAROXYSMAL ATRIAL

TACHYCARDIA (PAT), also called paroxysmal

supraventricular tachycardia (PSVT), that converts

the heart to normal sinus rhythm. Sometimes car-

diologists refer to this treatment as chemical or

pharmaceutical CARDIOVERSION. Adenosine is avail-

able in the United States as the brand name prod-

uct Adenocard. The effects of adenosine last only

one to two minutes. Side effects may include

headache, lightheadedness, NAUSEA, and shortness

of breath (DYSPNEA). Adenosine also may trigger

angina pectoris in people who have CAD.

Alpha Blockers

Alpha blockers, also called alpha adrenergic antag-

onist medications, block alpha receptors in the

cells from binding with EPINEPHRINE (also called

adrenaline). These drugs were among the first

generation of antihypertensive medications,

though beta blockers and other antihypertensives

have generally replaced them. Alpha blockers

relax smooth MUSCLE, including that in the walls of

the arteries to produce arterial dilation. This

reduces the resistance for the flow of blood, low-

ering blood pressure. The most common cardio-

vascular use of alpha blockers is to treat

hypertension that arises from PHEOCHROMOCYTOMA.

This endocrine tumor secretes the hormones epi-

nephrine and NOREPINEPHRINE, causing extreme

spikes in blood pressure.

Alpha blockers are not a first-line treatment

approach for general hypertension because their

effects are widely systemic and because their long-

term use increases the risk for heart failure. Alpha

blockers affect other sites of smooth muscle tissue

throughout the body, such as in the gastrointesti-

nal tract, acting to slow peristalsis, and in the gen-

itourinary system, causing URINARY INCONTINENCE

and ERECTILE DYSFUNCTION. Other side effects may

include dizziness and SYNCOPE (fainting). Some

alpha blockers also block beta receptors.

medications to treat cardiovascular disease 77