effects, contraindications, and more; available on the book’s Web site (see URL
in Appendix).
Heart Failure MedicationHeart failure is treated by using vasodilators to decrease venous blood return to
the heart. This results in a decrease in cardiac filling, decreased ventricular
stretching, and decreased oxygen demand on the heart.
Vasodilators work in three ways. They
- Reduce cardiac afterload, which increases cardiac output.
- Dilate the arterioles of the kidneys to improve renal perfusion and increase
fluid loss. - Improve circulation to the skeletal muscles.
Examples of vasodilators include: hydralozine (apresoline), and Minoxidil
(Lonitin).
Heart failure is also treated with angiotensin-converting enzyme (ACE)
inhibitors. Angiotensin-converting enzyme (ACE) inhibitors dilate venules
and arterioles to improve renal blood flow and decreases blood fluid volume.
Angiotensin-converting enzyme (ACE) inhibitors moderately decrease the release
of aldosterone; sodium retention is reduced as is fluid retention.
Diuretics are also prescribed to treat heart failure. Diuretics, which will be
discussed in detail later in this chapter, are the first line of treatment for reduc-
ing fluid volume and are frequently prescribed with digoxin. Spironalactone
(Aldactone) is a potassium-sparing diuretic and is effective in treating moderate
to severe heart failure. It is more effective than ACE inhibitors. Beta-blockers
have been contraindicated for patients in heart failure.
Antianginal DrugsAntianginal drugs (see Table 19-1) are used to treat angina pectoris by increasing
blood flow either by increasing oxygen supply or by decreasing oxygen demand
of the heart. Angina pectoris is acute cardiac pain caused by inadequate blood
flow as a result of plaque occlusion in the coronary arteries of the myocardium
or spasms of the coronary arteries. The decreased blood flow causes a decrease
in oxygen to the myocardium, which is the cause of the pain. Anginal attacks
may last for a few minutes and can lead to myocaradial infarction (heart attack).
There are three types of angina.
1.Classic (stable). Classic angina occurs with stress and exertion and is caused
by the narrowing or partial occlusion of coronary arteries.CHAPTER 19 Cardiac Circulatory Medications^351