Overview of vasodilator drugs: arterial, venous and other

From this article you will learn: what are the vasodilating drugs, how they affect the blood vessels, what diseases they are prescribed.

Article Contents:

• arterial vasodilators
• venous vasodilators
• Vasodilators mixed action
• Alpha-blockers
• Angiotensin converting enzyme( ACE) inhibitors and angiotensin receptor blockers( ARBs)
• agonists beta2-adrenoceptor
• Calcium channel blockers
• Centrally acting sympatholytic
• Vasodilators Directaction
• Endothelin receptor antagonists
• Gangliablockers
• Nitrates

Vasodilators preparatovami( vazodilatatorami) called drugs that relax the smooth muscles in the blood vessels.

Extended arteries lead to a decrease in blood pressure( abbreviated BP), and veins - to a decrease in venous pressure. This effect of vasodilators is most often used in medicine for the treatment of arterial hypertension( AH), heart failure( HF) and angina pectoris.

Blood pressure levels are normal and with hypertension

Some of the vasodilator drugs act primarily on the arteries, they are most often prescribed for the treatment of arterial hypertension, heart failure and angina pectoris. Others - act mainly on veins, they are most often prescribed for heart failure and angina. Most vasodilators have the ability to expand both arteries and veins, so they can be used for all these diseases.

In clinical practice, separation of vasodilators by the mechanism of action on vessels is more often used. According to this classification, the following types of vasodilators are distinguished:

Some of the means that expand the vessels have other properties - for example, they can reduce the frequency of heart contractions( HR) and their strength. This gives them definite advantages in the treatment of hypertension.

Prescribe vasodilators most often cardiologists and therapists.

Arterial vasodilators

Arterial dilatation drugs are often used to treat arterial and pulmonary hypertension, heart failure, and angina pectoris. They reduce blood pressure and vascular resistance, reducing the burden on the heart.

In patients with angina, arterial vasodilators reduce the need for myocardium( cardiac muscle) in oxygen, some of them can even eliminate the spasm of the coronary arteries, causing an attack of pain in the chest.

An example of a vasodilator with a selective effect on the artery is hydralazine, a drug belonging to a group of direct vasodilators.

Hydralazine in the bottle

Venous vasodilators

Drugs that dilate the venous vessels have the following effect:

• Reduce venous pressure, thereby reducing the burden on the heart. This property is useful for the treatment of angina pectoris, because it reduces the need for cardiac muscle in oxygen.
• Reduce the hydrostatic pressure in the capillaries, thereby reducing the yield of the liquid. This property is useful for eliminating edema on the legs and stagnation of blood in the lungs caused by heart failure.
• Reduces cardiac output and blood pressure.

An example of drugs with a primary effect on the venous channel are nitrates.

Vasodilators with mixed action

Most vasodilators can expand both arteries and veins. These drugs reduce vascular resistance and blood pressure, little effect on cardiac output.

Alpha blockers

These drugs block the effect of noradrenaline on alpha-adrenoreceptors placed on smooth muscle cells of blood vessels. Alpha-blockers dilate both veins and arteries, but these agents have a more pronounced effect on the arteries. They are used to treat hypertension. Examples of alpha-blockers are prazosin, doxazosin, phentolamine.

Side effects include dizziness, orthostatic hypotension( lowering blood pressure when changing body position), nasal congestion( associated with the expansion of arterioles in the nasal mucosa), headaches, heart palpitations.

Vasodilators from the group of alpha-blockers do not have useful properties for the treatment of heart failure or angina, therefore they are not used for these diseases.

Doxazosin in tablets

Angiotensin converting enzyme inhibitors and angiotensin receptor blockers

Both these groups of drugs act on the renin-angiotensin system, one of the effects of which is vasoconstriction. ACE inhibitors and ARBs have the following properties:

Assign these drugs for the treatment of AH, HF and myocardial infarction.

Examples of ACE inhibitors are ramipril, perindopril, lisinopril, captopril;BRA - candesartan, losartan, telmisartan. Most of these drugs are available in the form of tablets.

The main side effect of ACEI is dry cough, hypotension, angioedema and elevated levels of potassium in the blood. In the treatment of angiotensin receptor blockers, cough and angioedema develop very rarely.

Captopril tablets 25 mg and 50 mg

β2-adrenoreceptor agonists

These drugs activate beta-adrenoreceptors of the heart and smooth muscle in the blood vessels. They relax the muscles of the bronchial tree and stimulate the production of renin in the kidneys.

Stimulating beta-adrenergic receptors in the heart, these drugs increase heart rate and the force of its contractions, which contributes to the growth of blood pressure. Activating beta2-adrenergic receptors in blood vessels, they expand them and help reduce blood pressure. Thus, the effect of beta2-adrenoceptor agonists on the level of AD depends on the combination of their effects on the heart and blood vessels.

The most known agonists of beta2-adrenergic receptors are adrenaline, norepinephrine, dopamine, dobutamine and isoproterenol. Although these drugs also dilate the vessels when exposed to beta2-adrenoreceptors, this effect is blocked by the vasoconstrictive action caused by the activation of alpha-adrenergic receptors. In clinical practice, this dual effect is most pronounced in dopamine - in low doses this drug causes a slight expansion of the arteries in the kidneys, and in the high - the narrowing of the vessels throughout the body.

The main application of beta2-adrenergic agonists is the treatment of acute heart failure, which is accompanied by a decrease in blood pressure. Isoproterenol is also used to increase heart rate.

The main side effects are arrhythmias, an increase in myocardial oxygen demand and the development of an angina attack, headache and tremor.

Adrenaline solution in ampoules

Calcium channel blockers

These vasodilators block the channels responsible for regulating the ingestion of calcium into the vascular and heart cells. They cause vasodilation, reduce the force of contractions and impair the conductivity of impulses in the heart. Therefore, most often these drugs are used to treat hypertension, angina and arrhythmias.

There are several groups of calcium channel blockers, of which dihydropyridines are most widely dilated. To this group belong amlodipine, nifedipine, felodipine, nicardipine. These drugs are available in the form of tablets or drops for oral administration.

Side effects of dihydropyridines include blood flushing to the face, headache, falling blood pressure, swelling and increased heart rate.

Centrally acting sympatholytics

In the regulation of vascular tone an important role is played by the sympathetic nervous system, activation which causes an increase in heart rate and cardiac contraction, narrows the vessels. Centrally acting sympatholytics reduce its activity, due to which vasodilation develops. They are used to treat hypertension. Clonidine and methyldopa belong to them.

Side effects of centrally acting sympatholytes include sedation( sedative effect), drying of the mucous membrane in the mouth and nose, lowering of the blood pressure, erectile dysfunction, constipation, nausea and indigestion.

Vasodilators with direct action of

To this group belongs only hydralazine, which acts selectively and directly on the smooth muscle cells of the arteries, reducing vascular resistance and blood pressure. Most often, hydralazine is used to treat hypertension and heart failure. The most common side effects of this medication are headaches, flushing of the face and palpitations.

Endothelin receptor antagonists

Endothelin is a substance produced by the cells of the inner shell of vessels( endothelium), which has a strong vasoconstrictive effect. The action of endothelin receptor antagonists blocks this effect and causes vasodilation. Currently, these drugs( bosentan and ambriscent) are used only to treat pulmonary hypertension.

Side effects of endothelin receptor antagonists include headache, flushing to the face, edema development, hepatic insufficiency.

Gangliablockers

These drugs block sympathetic ganglia, which is why the vessels dilate and decrease blood pressure. Usually they are used only for a rapid and controlled reduction in blood pressure in hypertensive crises. To ganglioblockers belong trimetafan and benzohexonium. Side effects include a strong drop in blood pressure, constipation, urinary retention, dry mouth, erectile dysfunction.

Nitrates

The action of nitrates is due to the release of nitric oxide, which causes relaxation of smooth muscle cells and vasodilation. Although these drugs extend all the vessels, in therapeutic doses they affect mainly the veins, thereby reducing the burden on the heart. Nitrates cause the expansion of the coronary arteries and relieve their spasm, which eliminates the attack of angina.

They are prescribed for the treatment of hypertensive crises, acute and severe chronic heart failure, angina pectoris and myocardial infarction. These include nitroglycerin, isosorbide mononitrate, sodium nitroprusside, which are available in the form of tablets or solutions for intravenous administration. Side effects of nitrates include headache, flushing to the face, lowering blood pressure, increasing heart rate.

Results of

Vasodilator drugs are one of the most frequently prescribed medicines in medicine. With their help, the majority of patients with arterial hypertension, angina and heart failure are treated. The choice of the right drug should be made by the doctor, based on the type of disease in each individual patient.