In most patients with severe hypertension it is safest to lower the blood pressure gradually over an hour or so using oral medication, e. g. with hydralazine + propranolol. The lowering of blood pressure within minutes is necessary only when life is threatened by hypertensive encephalopathy, dissecting aneurysm of the aorta, continuing cerebral or subarachnoid haemorrhage, acute pulmonary oedema secondary to severe hypertension, or eclampsia. If hypertension is due to raised intracranial pressure it should not be treated unless the intracranial pressure has first been reduced. Rapid or excessive reduction of blood pressure can precipitate cerebral or myocardial infarction, particularly in old people, and in patients with long-standing hypertension.
