Byxin Tong is a nifedipine controlled release tablet, which is a calcium antagonist in the treatment of hypertension. Drugs in the same class as it are nifedipine, nicardipine, felodipine, amlodipine, of which amlodipine is a long-acting preparation, and also verapamil, diltiazem, etc. This class of drugs is recommended to be taken in the morning after meals. It has several adverse reactions, such as causing edema in the ankle and may also cause gum enlargement, so when using it, especially for long-term use, patients must keep their mouths clean. This drug must not be broken open and chewed when it is used, but must be taken whole with warm water.