![]() Absorption is not affected by food Label. Steady-state plasma amlodipine levels are achieved after 7-8 days of consecutive daily dosing. The estimated bioavailability of amlodipine is 64-90%. Peak plasma concentrations are achieved 6-12 hours after oral administration. TargetĪ Voltage-dependent L-type calcium channel subunit alpha-1CĪmlodipine absorbed slowly and almost completely from the gastrointestinal tract. The dilatation causes an increase in myocardial oxygen delivery in patients experiencing coronary artery spasm (Prinzmetal's or variant angina) and reduces coronary vasoconstriction caused by smoking 9. Since the heart rate remains stable during amlodipine administration, the reduced work of the heart reduces both myocardial energy use and oxygen requirements 9.ĭilatation of the main coronary arteries and coronary arterioles, both in healthy and ischemic areas, is another possible mechanism of amlodipine reduction of blood pressure. The exact mechanism by which amlodipine relieves the symptoms of angina have not been fully elucidated to this date, however, the mechanism of action is likely twofold:Īmlodipine has a dilating effect on peripheral arterioles, reducing the total peripheral resistance (afterload) against which the cardiac muscle functions. Direct actions of amlodipine on vascular smooth muscle result in reduced blood pressure 9. A stronger effect of amlodipine is exerted on vascular smooth muscle cells than on cardiac muscle cells Label. ![]() Amlodipine blocks calcium ion influx across cell membranes with selectivity. The contraction of cardiac muscle and vascular smooth muscle are dependent on the movement of extracellular calcium ions into these cells by specific ion channels. ![]() Experimental studies imply that amlodipine binds to both dihydropyridine and nondihydropyridine binding sites, located on cell membranes. Amlodipine is a dihydropyridine calcium antagonist (calcium ion antagonist or slow-channel blocker) that inhibits the influx of calcium ions into both vascular smooth muscle and cardiac muscle. Mechanism of actionĪmlodipine is considered a peripheral arterial vasodilator that exerts its action directly on vascular smooth muscle to lead to a reduction in peripheral vascular resistance, causing a decrease in blood pressure. In patients diagnosed with angina, daily administration of a single amlodipine dose increases total exercise time, the time to angina onset, and the time to 1 mm ST-segment depression on ECG studies, decreases anginal attack frequency, and decreases the requirement for nitroglycerin tablets 9. In clinical studies comprised of angina patients alone, amlodipine did not change electrocardiographic intervals or produce high degrees of AV block Label.Īmlodipine relieves the symptoms of chest pain associated with angina. In clinical trials in which amlodipine was given in combination with beta-blockers to patients diagnosed with hypertension or angina, no adverse effects on electrocardiographic parameters were noted. Patients administered amlodipine with concomitant beta-blockers produced similar results. In patients who were diagnosed with chronic stable angina, the intravenous administration of 10 mg of amlodipine did not cause clinically significant alterations A-H and H-V conduction and sinus node recovery time after cardiac pacing. With long-term, once daily oral administration, antihypertensive effectiveness is maintained for at least 24 hours Label.Īmlodipine does not change sinoatrial (SA) nodal function or atrioventricular (AV) conduction in animals or humans. Acute intravenous administration of amlodipine reduces arterial blood pressure and increases heart rate in patients with chronic stable angina, however, chronic oral administration of amlodipine in clinical studies did not cause clinically significant alterations in heart rate or blood pressures in patients diagnosed with angina and normal blood pressure. During these blood pressure reductions, there are no clinically significant changes in heart rate or plasma catecholamine levels with long-term use. This drug's unique binding properties allow for its long-acting action and less frequent dosing regimen 1, Label.Īfter the administration of therapeutic doses of amlodipine to patients diagnosed with hypertension, amlodipine causes vasodilation, which results in a reduction of supine and standing blood pressure. Amlodipine has a strong affinity for cell membranes, modulating calcium influx by inhibiting selected membrane calcium channels.
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