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Arteriolar Vasodilator
Arteriolar vasodilators are substances or medications that preferentially dilate arterioles. When used on people with certain heart conditions, it causes a phenomenon known as the cardiac steal syndrome. Arteriolar vasodilators increase intracapillary pressure, which causes fluid to enter the tissues, leading to vasodilatory edema. Arteriolar vasodilators include: * hydralazine * minoxidil * nitroprusside Sodium nitroprusside (SNP), sold under the brand name Nitropress among others, is a medication used to lower blood pressure. This may be done if the blood pressure is very high and resulting in symptoms, in certain types of heart failure, and ... References Vasodilators {{cardiovascular-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arterioles
An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries. Arterioles have muscular walls (usually only one to two layers of smooth muscle cells) and are the primary site of vascular resistance. The greatest change in blood pressure and velocity of blood flow occurs at the transition of arterioles to capillaries.This function is extremely important because it prevents the thin, one-layer capillaries from exploding upon pressure. The arterioles achieve this decrease in pressure, as they are the site with the highest resistance (a large contributor to total peripheral resistance) which translates to a large decrease in the pressure. Structure Microanatomy In a healthy vascular system the endothelium lines all blood-contacting surfaces, including arteries, arterioles, veins, venules, capillaries, and heart chambers. This healthy condition is promoted by the ample production of nitric oxide by the en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Steal Syndrome
Coronary steal (with its symptoms termed coronary steal syndrome or cardiac steal syndrome) is a phenomenon where an alteration of circulation patterns leads to a reduction in the blood flow directed to the coronary circulation. It is caused when there is narrowing of the coronary arteries and a coronary vasodilator is used – "stealing" blood away from those parts of the heart. This happens as a result of the narrowed coronary arteries being always maximally dilated to compensate for the decreased upstream blood supply. Thus, dilating the resistance vessels in the coronary circulation causes blood to be shunted away from the coronary vessels supplying the ischemic zones, creating more ischemia. Signs and symptoms Mild coronary steal might not have any symptoms, but as the syndrome progresses, chest pain could usually be the first obvious symptom. In worse cases symptoms can include dizziness, flushing, headaches, nausea and shortness of breath Cause It is associated with dipyri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edema
Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels tight, the area may feel heavy, and joint stiffness. Other symptoms depend on the underlying cause. Causes may include venous insufficiency, heart failure, kidney problems, low protein levels, liver problems, deep vein thrombosis, infections, angioedema, certain medications, and lymphedema. It may also occur after prolonged sitting or standing and during menstruation or pregnancy. The condition is more concerning if it starts suddenly, or pain or shortness of breath is present. Treatment depends on the underlying cause. If the underlying mechanism involves sodium retention, decreased salt intake and a diuretic may be used. Elevating the legs and support stockings may be useful for edema of the legs. Older people are more commonly affected. The wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydralazine
Hydralazine, sold under the brand name Apresoline among others, is a medication used to treat high blood pressure and heart failure. This includes high blood pressure in pregnancy and very high blood pressure resulting in symptoms. It has been found to be particularly useful in heart failure, together with isosorbide dinitrate, for treatment of people of African descent. It is given by mouth or by injection into a vein. Effects usually begin around 15 minutes and last up to six hours. Common side effects include headache and fast heart rate. It is not recommended in people with coronary artery disease or in those with rheumatic heart disease that affects the mitral valve. In those with kidney disease a low dose is recommended. Hydralazine is in the vasodilator family of medications, so it is believed to work by causing the dilation of blood vessels. Hydralazine was discovered while scientists at Ciba were looking for a treatment for malaria. It was patented in 1949. It i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minoxidil
Minoxidil, sold under the brand name Rogaine among others, is a medication used for the treatment of high blood pressure and pattern hair loss. It is an antihypertensive vasodilator. It is available as a generic medication by prescription in oral tablet form and over the counter as a topical liquid or foam. Medical uses Minoxidil, when used for hypertension, is generally reserved for use in severe hypertension patients who can not respond to at least two agents and a diuretic. Minoxidil is also generally administered with a loop diuretic to prevent sodium and potassium retention. It may also cause a reflex tachycardia and thus is prescribed with a beta blocker. Minoxidil, applied topically, is widely used for the treatment of hair loss. It is effective in helping promote hair growth in people with androgenic alopecia regardless of sex. Minoxidil must be used indefinitely for continued support of existing hair follicles and the maintenance of any experienced hair regrowt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitroprusside
Sodium nitroprusside (SNP), sold under the brand name Nitropress among others, is a medication used to lower blood pressure. This may be done if the blood pressure is very high and resulting in symptoms, in certain types of heart failure, and during surgery to decrease bleeding. It is used by continuous injection into a vein. Onset is nearly immediate and effects last for up to ten minutes. It is available as a generic medication. Side effects and mechanism Common side effects include low blood pressure and cyanide toxicity. Other serious side effects include methemoglobinemia. It is not generally recommended during pregnancy due to concerns of side effects. High doses are not recommended for more than ten minutes. It works by increasing nitric oxide levels in the blood, which increases cGMP levels in cells, and causes dilation of blood vessels. History, society and culture Sodium nitroprusside was discovered as early as 1850 and found to be useful in medicine in 1928. It is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
