Steady-state plasma levels of amlodipine are reached after 7 to 8 days of consecutive daily dosing. Elimination from the plasma is biphasic with a terminal elimination half-life of about 30 to 50 hours. Ex vivo studies have shown that approximately 93% of the circulating drug is bound to plasma proteins in hypertensive patients. Amlodipine is extensively (about 90%) converted to inactive metabolites via hepatic metabolism with 10% of the parent compound and 60% of the metabolites excreted in the urine. The bioavailability of amlodipine is not altered by the presence of food. Absolute bioavailability has been estimated to be between 64 and 90%. Pharmacokinetics and MetabolismĪfter oral administration of therapeutic doses of amlodipine, absorption produces peak plasma concentrations between 6 and 12 hours. This inhibition of coronary spasm is responsible for the effectiveness of amlodipine in vasospastic (Prinzmetal's or variant) angina. ![]() Vasospastic Angina: Amlodipine has been demonstrated to block constriction and restore blood flow in coronary arteries and arterioles in response to calcium, potassium epinephrine, serotonin, and thromboxane A2 analog in experimental animal models and in human coronary vessels in vitro. Create your project in seconds from existing files using the New Project Wizard or create your book from scratch using the built-in styled text editor.Įxertional Angina: In patients with exertional angina, amlodipine reduces the total peripheral resistance (afterload) against which the heart works and reduces the rate pressure product, and thus myocardial oxygen demand, at any given level of exercise. Anthemion Jutoh 2.93.2 (x86/圆4) Multilingual 82.6 Mb Jutoh makes it easy to create ebooks in popular formats that you can sell on many ebook sites. So do make copies of important projects that you are testing Jutoh 2. Please be aware of the following: If you open a Jutoh 1 project in Jutoh 2, you cannot then open it again in Jutoh 1 (unless you opened it in read-only mode). Jutoh 2 will be a free upgrade for all users - just enter your Jutoh 1 user name and key to unlock it. The precise mechanisms by which amlodipine relieves angina have not been fully delineated, but are thought to include the following: Amlodipine is a peripheral arterial vasodilator that acts directly on vascular smooth muscle to cause a reduction in peripheral vascular resistance and reduction in blood pressure. Within the physiologic pH range, amlodipine is an ionized compound (pKa=8.6), and its kinetic interaction with the calcium channel receptor is characterized by a gradual rate of association and dissociation with the receptor binding site, resulting in a gradual onset of effect. Serum calcium concentration is not affected by amlodipine. Negative inotropic effects can be detected in vitro but such effects have not been seen in intact animals at therapeutic doses. ![]() Amlodipine inhibits calcium ion influx across cell membranes selectively, with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. Experimental data suggest that amlodipine binds to both dihydropyridine and nondihydropyridine binding sites. Amlodipine is a dihydropyridine calcium antagonist (calcium ion antagonist or slow-channel blocker) that inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle.
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