[Hypertensive crisis: definition, pathophysiology and treatment]

Hypertensive crises are currently subdivided into hypertensive emergencies and urgencies depending on the acuteness with which the elevated blood pressure has to be lowered. Malignant hypertension, defined as severe hypertension and a hypertensive fundus grade III or IV, can present itself as an emergency or an urgency. For a hypertensive emergency intravenously acting blood pressure lowering agents are almost always required, whereas an urgency can usually be treated with oral agents. In view of the danger of cerebral hypoperfusion, blood pressure reduction during the initial treatment phase of a hypertensive crisis should not be more than 20 to 25%. Agents that exert a controllable blood pressure lowering action are preferred. Controllable blood pressure lowering cannot be achieved with nifedipine capsules. The practice of biting and swallowing a nifedipine capsule for the treatment of a hypertensive crisis therefore is to be discouraged.