1) Not to be used in newborns, infants, pregnant women, or those with an allergic constitution. 2) Not for administration by intravenous injection. The administration speed should not be too fast. In those receiving the drug for the first time, the initial administration should be at 15 drips/min for 10 min. If there are no abnormalities, the speed of administration can be increased to normal, which is generally controlled at 40–50 drips/min. 3) This drug has a pressor response, and blood pressure should be monitored in hypertensive patients.