Generally, the best effect can be achieved after 3-5 days of Irbesartan administration. Irbesartan is an angiotensin II receptor antagonist, a first-line long-acting antihypertensive drug, which is mainly used in clinical practice for the treatment of hypertension. In addition, it can also reduce proteinuria and prevent left ventricular remodeling as a secondary prevention drug for patients with heart failure and angina pectoris. Generally, the drug concentration will stabilize after 3-5 days of continuous use, i.e., the best effect will be achieved after 3-5 days. If the patient’s blood pressure is still high after 3-5 days, it is recommended to add an additional antihypertensive drug, such as felodipine or nifedipine tablets, as prescribed by the doctor. Patients may experience dizziness, persistent dry cough, heartburn, diarrhea, etc. Some patients may also experience chest pain, nausea, vomiting, palpitations, panic and other uncomfortable symptoms during the medication period. It is recommended that patients with high blood pressure should pay attention to rest, avoid staying up late, ensure sufficient sleep, maintain a relaxed mood, and eat a low-salt, low-fat diet.