Demser is an anti-hypersensitive drug that prevents the enzyme tyrosine hydroxylase and catecholamine synthesis. As a consequence it lowers the levels of the catecholamine dopamine, noradrenaline, and adrenaline in the body. It is a therapy employed to help manage the hypertension of patients before and after surgery. Secretion of catecholamines mostly results in hypertension both paroxysmal and continuous. Catecholamine-releasing endocrine tumors are called Pheochromocytomas.