Encyclopedia of Health and Medicine

82 The Cardiovascular System
Fibrates The fibrates work by blocking the
liver’s production of LDL and VLDL (very lowdensity
lipoprotein), the carriers for triglycerides.
However, fibrates do not lower LDL-C or VLDL-C
in the blood. Rather, they primarily reduce triglycerides
though also raise high-density lipoprotein
cholesterol (HDL-C), the “good” cholesterol. The
most common side effect of fibrates is gastrointestinal
distress, which usually disappears after
taking the medication for a few weeks.
COMMON FIBRATES
clofibrate (Atromid-S)
fenofibrate (Tricor)
gemfibrozil (Lopid)
Statins Statins—or 3-hydroxy-3-methylglutaryl
coenzyme A (HMG-CoA) reductase inhibitors—are
the most commonly prescribed lipid-lowering medications.
They work by blocking the action of HMG-
CoA reductase, an enzyme necessary for the liver to
synthesize cholesterol. Statins can lower blood LDL
cholesterol by as much as 35 percent in just three to
six weeks, making them very effective at quickly
lowering the risk for atherosclerosis-related cardiovascular
events. Statins reduce the risk for the progression
of CAD, which could improve heart
function after heart attack and are part of the standard
medication regimen after heart attack and
HEART TRANSPLANTATION. Common side effects of
statins include gastrointestinal distress, fatigue,
headache, and sleep disturbances.
COMMON STATINS
atorvastatin (Lipitor)
fluvastatin (Lescol)
lovastatin (Mevacor)
pravastatin (Pravachol)
simvastatin (Zocor)
Selective cholesterol absorption inhibitors The
selective cholesterol absorption inhibitors block
the gastrointestinal tract from absorbing dietary
cholesterol, limiting the cholesterol that enters the
bloodstream. Ezetimibe (Zetia) is currently the
only drug in this classification that is available in
the United States. Doctors often prescribe ezetimibe
in combination with statin medications for the
most effective lipid-lowering effect.
Potassium Channel Blockers
Potassium channel blockers, also called potassium
channel antagonists or class III antiarrhythmics,
limit the amount of potassium, a key electrolyte
(chemical that can carry an electrical impulse), that
can enter myocardial cells. This limitation restricts
the flow and pattern of electrical impulses through
the heart in very specific ways. Cardiologists prescribe
potassium channel blockers to treat atrial fibrillation
that does not respond to other medications
and to treat atrial tachycardia. These drugs interact
with numerous medications, including those prescribed
to treat cardiovascular conditions (notably
digoxin and warfarin) and to treat other health
conditions such as DIABETES. Amiodarone increases
sensitivity to ultraviolet light, which can result in
severe SUNBURN even through clothing. Potassium
channel blockers have numerous serious side
effects including life-threatening or fatal arrhythmias
and TORSADE DE POINTES, a highly unstable form
of ventricular tachycardia.
COMMON POTASSIUM CHANNEL BLOCKERS
amiodarone (Cordarone)
dofetilide (Tikosyn)
ibutilide (Corvert)
Sodium Channel Blockers
Sodium channel blockers, also called sodium
channel antagonists or class I antiarrhythmics,
limit the amount of sodium that enters myocardial
cells. This limitation restricts the flow and pattern
of electrical impulses through the heart in very
specific ways that differ from the actions of potassium
channel blockers. Because sodium is critical
for myocardial contraction, restricting it requires a
delicate therapeutic balance. Cardiologists reserve
sodium channel blockers to treat potentially lifethreatening
ventricular tachycardia that does not
respond to other treatment. The risks and complications
of these medications are numerous and
serious; they can cause fatal arrhythmias.
COMMON SODIUM CHANNEL BLOCKERS
disopyramide (Norpace)
flecainide (Tambocor)
mexiletine (Mexitil)
moricizine (Ethmozine)
procainamide (Pronestyl)
propafenone (Rythmol)
quinidine (Cardioquin, Quinidex)
Thrombolytic Agents
Thrombolytic agents, commonly called “clot
busters,” dissolve blood clots that have already
formed. Given early enough, they can prevent the