The administration of diphenhydramine should be selected in conjunction with the indications of the drug as well as the patient’s condition. The common diphenhydramine drugs are nifedipine, amlodipine, nicardipine, etc., all belong to calcium channel blockers, which selectively block calcium channels, inhibit the inward flow of extracellular calcium ions, and reduce the concentration of intracellular calcium ions to play a role. 1. Nifedipine has antihypertensive effect on moderate and severe hypertension, and is used in patients with angina pectoris, diabetes mellitus and asthma. Headache, constipation and other adverse reactions will occur, prohibited for use in patients with cardiogenic shock. 2. Amlodipine is used in the treatment of hypertension and the treatment of chronic stable angina pectoris, variant angina pectoris and angiographically confirmed coronary heart disease. Common adverse reactions are edema, dizziness, palpitations, and it is contraindicated for those who are allergic to amlodipine. 3. Nicardipine is used in the treatment of hypertension as well as exertional angina. Common adverse reactions include ankle edema, headache, etc. It is contraindicated in patients with severe aortic stenosis. Patients are advised to follow medical advice.