Many hypertensive drugs require lifelong medication. There are actually five classes of anti-hypertensive drugs: the first class is diuretics, the second class is calcium antagonists, the third class is converting enzyme inhibitors, the fourth class is angiotensin II receptor antagonists, and beta-blockers. Long-term use may cause the following side effects: 1. diuretics: long-term use may cause low blood potassium, which may cause arrhythmia; 2. calcium antagonists: long-term use may cause adverse reactions such as flushing, ankle edema or tachycardia; 3. converting enzyme inhibitors: long-term use may cause dry cough; 4. angiotensin II receptor antagonists: long-term use may cause cough or 4. angiotensin II receptor antagonists: long-term use may cause cough or local edema; 5. beta-blockers: long-term use may cause slowed heartbeat or heart failure, or may induce respiratory diseases, such as bronchial asthma.