Antihypertensive drugs are categorized into short-acting, medium-acting, medium-long-acting and long-acting antihypertensive drugs. Short-acting antihypertensive drugs work for half an hour, while medium- and long-acting antihypertensive drugs work for several hours. Short-acting antihypertensive drugs are generally taken within half an hour, will be able to have a significant effect on lowering blood pressure, commonly used drugs are nifedipine, captopril and so on. Short-acting antihypertensive drugs are usually used in emergency to reduce blood pressure, and the maintenance time is short. Medium- and long-acting antihypertensive drugs take effect within 2 to 4 hours, and long-acting drugs take effect relatively slowly. But the maintenance time is long. Commonly used drugs are metoprolol, hydrochlorothiazide and so on. Long-acting antihypertensive drugs, if taken for the first time, usually need to be taken for 2~4 weeks to have a stable effect. The initial lowering of blood pressure in patients with severe hypertension should be done slowly; if it is suddenly lowered too quickly, hypotensive syndromes such as dizziness and nausea can occur. Medications should be used under the direction of a physician.