Patients with severe hypertension require rapid hypotension and hospitalization, and oral medications for rapid hypotension include captopril tablets, nitroglycerin, etc. Sublingual or oral nifedipine was commonly used in the past, but numerous clinical trials have proven that nifedipine is not beneficial for acute myocardial infarction, congestive heart failure and secondary prevention of coronary heart disease, and oral or sublingual nifedipine can also cause syncope, myocardial infarction and even death, so the use of short-acting calcium antagonists is currently advocated for hypertensive emergencies and similar hypertensive emergencies. After winning valuable time, the patient can be taken to the hospital, and under the guidance of the doctor, intravenous rapid antihypertensive drugs such as sodium nitroprusside, nitroglycerin, uradil, phentolamine, etc. are used. 1. Nitroprusside is mainly used clinically for hypertensive patients with acute myocardial infarction and heart failure in hypertensive crisis. This drug is an arteriovenous dilator, lowering blood pressure by reducing peripheral vascular resistance. The hypotensive effect is strong and rapid, and the maintenance time is only 1~2 min, so it must be administered intravenously. The drip rate will be adjusted according to the blood pressure, and the blood pressure will drop within 30 s. If the drip is stopped for 2-3 min, the blood pressure will rise to the original level. (1) Nausea, vomiting, mental agitation, muscle cramps and headache may occur during the use of the drug. Large amounts or long-term use, especially for patients with renal failure, can cause thiocyanide poisoning and hypotension. Blood pressure and heart rate should be closely monitored during administration. (2) Prepare the solution before use and finish the drip within 6 hours, avoid light. (3) It is prohibited for pregnant women and should be used with caution in cases of renal insufficiency and hypothyroidism. 2, nitroglycerin clinical mainly used for hypertension combined with acute myocardial infarction, unstable angina, coronary artery spasm caused by myocardial ischemia, as well as hypertensive crisis, congestive heart failure, etc., the commonly used dose of 10 mg in 500 ml of liquid intravenous drip, the effect is rapid. The dose of 10 μl/min often starts from a small dose of 10 μg/min and increases by 10 μg/min every 5-10 min, reaching 50-200 μg/min. The dose is greater than 40 μg/min, not only on the venous system, but also on the resistance vessels. 3. Uraldil is used in various hypertensive emergencies and perioperative hypertension. It can be firstly injected 25 mg intravenously, observed for 5 min and then, if necessary, another 25 mg intravenously until the blood pressure reaches the desired value. In order to maintain the therapeutic effect or slowly lower the blood pressure, 200 mg can be dissolved in 500 ml of liquid and ordered quietly. Phentolamine is a non-selective alpha-adrenergic receptor blocker, with sympathomimetic, parasympathomimetic and histamine effects, direct vasodilatation in small doses, alpha-adrenergic receptor blocking effects in large doses. This drug is a powerful vasodilator, which can dilate both arteries and veins and lower blood pressure. It is often used in patients with hypertensive crisis caused by pheochromocytoma and combined with heart failure. The dosage is 10-20 mg dissolved in 100-200 ml of 5% glucose solution and administered intravenously at a rate of 0.l-0.3 mg/min, and the blood volume must be replenished before administration.