Drugs that cause upright hypotension include diuretics, nitrates, and alpha receptor antagonists. 1. Diuretics: such as hydrochlorothiazide. Lower blood pressure by reducing extracellular fluid volume. When standing suddenly, the manifestation of hypotension can occur due to low blood volume. Commonly used in the early stage of diuretic use or when the dosage is too large. 2. Nitrates: such as nitroglycerin. Reduce blood pressure by dilating blood vessels. It can lead to postural hypotension. 3. α-receptor antagonists: e.g. Phentolamine. Lowers blood pressure by dilating blood vessels and causes postural hypotension. Commonly found in the early stages of drug use. When using these antihypertensive drugs, you should be vigilant and should not stand up too quickly to prevent upright hypotension. If prolonged upright hypotension is not relieved, you should go to the hospital promptly.