Diltiazem, usually lasts 12-24 hours, the exact time can not be determined, need to be based on the dose. Diltiazem can relieve and prevent contraction of myocardial and vascular smooth muscle cells, dilate coronary arteries and peripheral blood vessels, improve myocardial hypertrophy, prolong the sinus node conduction time, and can effectively treat hypertension, angina pectoris, arrhythmia. In vivo, when combined with other drugs that are biotransformed through the same pathway, it can lead to competitive inhibition of metabolism with differences in maintenance time. A single oral dose of 30-120 mg of Diltiazem is detectable in plasma within 30-60 minutes. Blood concentrations peak within 2 to 3 hours, and the plasma clearance half-life for single or multiple doses is 3.5 hours. The effective blood concentration is 50 to 200 ng/ml. The common side effects of Diltiazem are basically itchy skin or hives, and then some patients may even experience breathing difficulties and spasms due to the severity of the condition. Patients are advised to adjust the dosage of the drug under the guidance of the doctor so as not to aggravate the condition due to self-reducing or stopping the drug.