The time of side effects of spironolactone tablets is related to individual’s constitution and cannot be generalized. Spironolactone tablets are mainly used for the prevention of edematous disorders, hypertension, primary aldosteronism, and hypokalemia. A common side effect is hyperkalemia, which is more likely to occur especially when the drug is used alone, on a high potassium diet, or when renal function is impaired. Therefore, monitoring of blood potassium and electrocardiogram is required during drug administration. Gastrointestinal reactions, such as nausea, vomiting and diarrhea, may occur in some cases. There are also allergic reactions, temporary elevation of plasma creatinine and urea nitrogen, mild hyperchloremic acidosis, etc. Tumors may occur in rare cases. Spironolactone tablets require individualized dosing, starting with the smallest effective dose. Generally take the drug in the morning to avoid frequent urination at night. Blood potassium concentration and electrocardiogram should be monitored before administration, and the drug should be discontinued immediately if hyperkalemia occurs during administration.