A reactive oxygen generating enzyme inhibitor with NO donor bioactivity, e.g., nitrated allopurinol, e.g., 1,5-bis(3-nitrooxypropyyl)-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidine-4-one is useful to treat heart failure, stable angina, ischemic disorder, ischemic reperfusion injury, atherosclerosis, sickle cell disease, diabetes, Alzheimer's disease, Parkinson's disease, ALS and asthma and to obtain proper contraction of heart, skeletal and smooth muscle. Where the disorder is heart failure, administration of the enzyme inhibitor mediates amelioration of acute coronary symptoms and/or myocardial infarction.
