Blood pressure may be high or low, firstly, due to atherosclerosis of blood vessels. Second, it may also be caused by incorrect use of blood pressure drugs, especially short-acting antihypertensive drugs. In order to clarify the specific cause, it is recommended to consider going to the cardiovascular medicine department of a qualified hospital for further examination, to clarify what causes the sudden high and low blood pressure, and to routinely monitor 24-hour ambulatory blood pressure, as well as check the electrocardiogram, cardiac ultrasound and other examination items to see if there are cardiac or vascular problems. If it is suspected that the blood pressure is unstable due to the use of antihypertensive drugs, it is recommended that it is best to choose to take long-acting drugs for oral blood pressure control treatment, because short-acting drugs may lead to a sharp drop in blood pressure within a short period of time, and after the effect of the drug leads to a rapid rise in blood pressure, which leads to unstable blood pressure. Anti-hypertensive drugs are recommended to choose nifedipine controlled-release tablets, amlodipine extended-release tablets and other medium- and long-acting drugs, all of which can smoothly control blood pressure and reduce blood pressure fluctuations.