IT IS MORE ACTIVE & LONGER ACTING THAN ISOSORBIDE DINTRATE. IT IS EFFECTIVE IN CLASSICAL AS WELL AS VIRIANT ANGINA & INCREASES EXERCISE TOLERANCE, POSTPONES ECG CHNGES OF ISCHAEMIA. NITRATES CAUSE DIRECT NON-SPETIFIC SMOOTH MUSCLE RELAXATION. THIS EFFECT OCCURS DUE TO PRODUCTION OF NITRIC OXIDE WHICH STIMULATES FORMATIONS OF CGMP IN THE SMOOTH MUSCLE CELLS WHICH LEADS TO DEPHOSPHORYLATION OF MYOSIN LIGHT CHAIN RESULTING IN MYOSIN LIGHT CHAIN RESULTING IN SMOOTH MUSCLE RELAXTION,REPEATED, FREQUENT ADMINISTRATION OF HIGH DOSE OF ORGANIC NITRATES LEADS TO DECREASE IN MAGNITUDE OF MOST OF THEIR PHARMACOLOGICAL ACTIONS. NITRATES CAUSE MORE VENODILATATION THAN ARTERIOLAR DILATATION, HENCE PRE-LOAD AND DIASTOLIC PRESSURE IS REDUCED WHICH LEADS TO DECREASED CARDIAC WORK.