Abstract

In only a few clinical situations is it necessary to lower an elevated blood pressure within minutes. These include hypertensive crises such as encephalopathy, continued haemorrhage from a bleeding subarachnoid vessel, and acute hypertensive left ventricular failure which has proved refractory to therapy with oxygen, diuretics and digitalis. In most other circumstances where the blood pressure must be reduced rapidly, as for example in hypertension with papilloedema or exudative retinopathy, it is better to use a drug which will lower blood pressure gradually over a few hours rather than one which acts within minutes. Controlled comparisons of drugs in such emergencies are difficult, and the choice has to be made on experience.