(pain and weakness of limbs when walking and symptoms are absent at rest),
and possible leg ulcers. The primary cause is hyperlipemia resulting in athero-
sclerosis and arteriosclerosis. The arteries become occluded.
Peripheral vasodilators increase blood flow to the extremities and are used for
venous and arterial disorders. They are more effective for disorders resulting from
vasospasm (Raynaud’s disease) than from vessel occlusion or arteriosclerosis
(arteriosclerosis obliterans, thromboangiitis obliterans [Buerger’s disease]). Some
of the drugs that promote vasodilation include tolazoline (Priscoline), an alpha-
adrenergic blocker (Chapter 15); isoxsuprine (Vasodilan) and nylidrin (Arlidin),
beta-adrenergic agonists (Chapter 15); and cyclandelate (Cyclan), nicotinyl
alcohol, and papaverine (Cerespan, Genabid), direct-acting peripheral vasodila-
tors. The alpha blocker prazosin (Minipress) and the calcium channel blocker
nifedipine (Procardia) have also been used.
A list of vasodilator drugs is provided in the Appendix. Detailed tables show
doses, recommendations, expectations, side effects, contraindications, and more;
available on the book’s Web site (see URL in Appendix).
Summary
The cardiovascular system consists of the heart, blood vessels, and blood that are
used to distribute oxygen, nutrients, and hormones and transports waste products
so they can be removed from the body.
Cardiac drugs regulate heart contraction, heart rate, and heart rhythm and reg-
ulate blood flow to the heart muscle. There are three groups of cardiac drugs:
glycosides, antianginals, and antidysthythmics.
Glycosides are known as digitalis glycosides. They inhibit the sodium-
potassium pump and increase intracellular calcium. As a result, there is an
increase in cardiac muscle contraction, decrease in the heart rate, and a decrease
in conduction of electrical stimulus to the heart.
Antianginal drugs are used to treat angina pectoris by increasing blood flow
either by increasing oxygen supply or by decreasing oxygen demand of the
heart. Antidysrhythmics are drugs that restore normal cardiac rhythm and are
used to treat cardiac dysrhythmias.
Antihypertensive drugs are used to treat hypertension by using a stepped-care
approach where groups of antihypertensive drugs are used in succession if blood
pressure isn’t at first decreased. Angiotensin antagonists are used primarily to
treat hypertension and some are also effective in treating heart failure.
CHAPTER 19 Cardiac Circulatory Medications^369