<prompt> Nitroprusside active metabolite acts by:Phosphokinase 1,2Guanylyl cyclasePhospholipase APhospholipase B  <response>: Ans. B. Guanylyl cyclase Nitrovasodilator arteriodilator venodilator Sodium nitroprusside is metabolized into nitric oxide, which activates guanylyl cyclase directly or through release of NO which leads to increase in cyclic GMP levels Cyclic GMP activates protein kinase G which dephosphorylates MLCP myosin light chain phosphorylase and relaxes the smooth muscles of blood vessels Vasodilatation occurs Dose: 0.3mcgkgmin Onset of action: 30 sec Therapeutic uses: Severe hypertension with acute myocardial infarction or left ventricular failure 