The drugs used in #anginapectoris either enhance myocardial oxygen supply or reduce myocardial oxygen demand.
The dresden angina pectoris either enhanced myocardial oxygen supply or reduce myocardial oxygen demand nitrates calcium channel blockers beta blockers and newer drugs ranolazine in trimet azzedine which modify myocardial metabolism are primarily used in treatment of angina pectoris nitrates the nitroglycerin rgl sorrel trinit rate gtn is prototype agents of the
Class isos or bide mononitrate isos or by dye nitrate in pentaerythritol tetra nitrate or other commonly used nitrate mechanism of action nitrates release nitric oxide no within smooth muscle cells nitric oxide stimulates the intracellular soluble guanylate cyclase which leads to an increase in formation of intracellular cyclic guanosine monophosphate cgmp cgmp
Activates c gmp dependent kinases decrease phosphorylation of myosin light chains by increasing activity of myosin light-chain phosphatase an enzyme that removes phosphate the reduced phosphorylation of myosin light chains causes vasodilation nitroglycerin dilates both venous smooth muscle and arteriole or smooth muscle however effect on the venous capacitance system
Predominates the dilation of the capacitance vessels leads to pooling of blood in the veins and reduced venous return to the heart and decreased preload reduction in ventricular pressure results in a decrease in the myocardial wall tension and oxygen requirement the reduction in left ventricular end diastolic pressure reduces extra vascular compression around the
Sub endocardial vessels favors redistribution of coronary blood flow to this area adverse effects the most common adverse effects of organic nitrates are headache hypotension dizziness and reflex tachycardia tolerance to nitrate induced headache develops after a few days of therapy adrina scepter blocking agents all beta blockers are effective in the treatment
Of classical angina the beta adrenergic blockers decrease the oxygen demands of the myocardium by decreasing heart rate contractility cardiac output and blood pressure beta 1 blockers such as metoprolol and atenolol are preferred however beta blockers are ineffective in bezos fasting angina calcium channel blockers the calcium channel blockers primarily affect the
Resistance of peripheral and coronary artery ole or smooth muscle the calcium channel blockers reduce myocardial oxygen consumption by decreasing vascular resistance after load there efficacy in bezos plastic angina is due to relaxation of the coronary arteries dihydropyridine calcium channel blockers and low dipping follow tapping is radicand micarta peen nifedipine
And nemoto pienaar having arterial or vasodilators action with a minimal effect on cardiac conduction heart rate amlodipine and nifedipine is useful in the treatment of variant angina caused by spontaneous coronary spasm verapamil slows atrial ventricular av conduction directly and decreases heart rate contractility blood pressure and oxygen demand diltiazem also
Slows av conduction decreases the rate of firing of the sinus node pacemaker and is also a coronary artery vasodilator diltiazem can relieve coronary artery spasm and is particularly useful in patients with variant angina drugs that modify myocardial metabolism ranolazine blocks the pathologic activation or prolongation of the late inward sodium current in heart
Cells that leads to excessive intracellular sodium and calcium accumulation and contributes to an imbalance between oxygen supply and demand during ischemia rinda trimet azzedine the heart uses glucose fatty acids and lactated sources of energy although fatty acids are the major fuel for the heart glucose is metabolized more efficiently and generates more energy
Per unit of oxygen used trimet azzedine inhibits keto a cell coenzyme a thiolase a key enzyme in the beta oxidation pathway of fatty acid metabolism the resulting decrease in fatty acid oxidation of oaks a compensatory increase in glucose metabolism and reduces oxygen consumption like share & subscribe the channel
Transcribed from video
Antianginal drugs, pharmacological mechanism of action of nitroglycerin, Ranolazine, Trimetazidine By Just Pharmacology