What is the action of organic nitrates

Action on the venous system, venodilation leads to lower preload Reduces workload of the heart Heart fills less therefore force of contraction is reduced This lowers oxygen demand Venodilation reduces venous pressure and the return of blood to the heart Action on coronary arteries improves O2 delivery to the ischaemic myocardium and acts on collateral arteries rather than arterioles so dilation increases amount of blood flow