Vasodilators are drugs or medicines
that act directly on muscles in blood vessel walls to make blood vessels
Types of Vasodilator Drugs
Vasodilator drugs are classified on the
basis of their way they work to widen blood vessels. Accordingly we have the
following types of vasodilators:
- ACE inhibitors (angiotensin-converting enzyme inhibitors):
They work by blocking the body's production of a chemical called
angiotensin II. This chemical leads to narrowing down of blood vessels
and hence ace inhibitors are used to block its production. As a result,
more blood can flow into the vessels. For heart failure patients,
doctors prescribe ACE inhibitors more often than any other type of
- Angiotensin II receptor: They produce the same effect as ACE
inhibitors, but they work in a different way. They block angiotensin II
from being able to act in the muscles that line the blood vessels
instead of preventing the production of it and in a way they decrease
the heart's workload.
- Alpha blockers: Another type of vasodilator is alpha
blockers. They reduce the heart's workload by blocking certain chemicals
- Calcium channel blockers: They block signals that tell blood
vessels in the heart to tighten and thereby reduce the workload of the
heart. They have a direct slowing effect on the heart muscle.
- Nitrates: They work by dilating the veins of the body. They
work on the muscles of the heart's blood vessels directly and thereby
allow them to relax and increase the flow of oxygen-rich blood to the
- Thiazide diuretics: These vasodilators increase the kidney's
production of urine, thus reducing fluid and minerals from the body.
Low-dose thiazide diuretics also work as vasodilators.
- Central adrenergic inhibitors: They interfere with signals
from the brain that notifies the blood vessels to tighten. This type of
vasodilator drugs is also used for other health problems like panic
attacks and migraine headaches.
Side Effects of Vasodilator Drugs
Side effects of vasodilator drugs are just temporary like as follows:
- Loss of appetite
- Nausea or vomiting
It is to be noted that the patients who are taking vasodilators shouldn't
take any other medicines or any kind of herbal remedies without first
consulting with their doctor. The following products can actually increase
the effects of vasodilators and lead to severe low blood pressure:
- Other vasodilators
- Medicines for sexual dysfunction
- Nicotinic acid
- Grapefruit juice
Common Vasodilator Drugs
- There are certain substance which counteract the effects of some
vasodilators and increase blood pressure. They are Aspirin, Nicotine and
Examples of Vasodilators are Hydralazine (Apresoline) and Minoxidil (Loniten).