e. Atherosclerosis. Atherosclerosis is a form of arteriosclerosis characterized
by localized accumulation of lipids (fats), leading to a narrowing of the arteries and
possible occlusion (blockage) of the vessels.
f. Peripheral Vascular Disease. Peripheral vascular disease (PVD) is a
condition characterized by a narrowing or occlusion of peripheral arterioles leading to
limited circulation to the extremities such as toes, fingers, and shoulders. You have
probably seen elderly patients who wear extra clothing during hot weather. The cold
feeling they have, even in hot weather, is probably due to lack of adequate circulation.
Section II. VASODILATOR DRUGS
4-3. INTRODUCTION
Now that you have some background in some cardiovascular disease, you will
review some general categories of vasodilators and some of the specific agents that
belong to each group.
4-4. SMOOTH MUSCLE RELAXANT VASODILATORS
Although the agents in this category affect almost all smooth muscle, our concern
here is only with their relaxant effect upon the smooth muscle of the coronary vessels
as well as peripheral (to the heart) blood vessels.
a. Amyl Nitrite. Amyl nitrite is a vasodilator administered only by inhalation. It
is rapidly absorbed from the lungs. This product is supplied in perles (like many
ammonia inhalants). When a person suffering from angina pectoris feels an attack
about to occur, he will crush an amyl nitrite perle and inhale its vapors. The attack of
angina pectoris is warded off or aborted in from one to two minutes. Because amyl
nitrite perles may explode when stored above normal room temperature, it is very
difficult for the patient to carry them in his pocket. This adverse situation normally
prohibits their use in the treatment of angina pectoris. The side effects associated with
amyl nitrite are usually attributed to the relaxation of all smooth muscle causing
vasodilation. Headache and dizziness are very common side effects associated with
amyl nitrite. Amyl nitrite does have an additional use, which is the treatment of cyanide
poisoning.
b. Glyceryl Trinitrate (Nitroglycerin). Glyceryl trinitrate is the most common
smooth muscle relaxant vasodilator used in the treatment of acute angina pectoris. This
drug is the product described in the introductory remarks of this subcourse lesson when
the man placed the small tablet under his tongue. Sublingual nitroglycerin tablets may
be used to allow a person who has angina to do extra work or to alleviate an acute
angina attack. Nitroglycerin's sublingual onset of action is from 1 to 3 minutes with
duration of action of from 9 to 11 minutes. Side effects associated with this drug include
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