The two most common side effects of ivabradine hydrochloride tablets include flashing light, also called optical hallucinations, and bradycardia, both of which are dose-dependent. Flashing occurs in 14.5% of patients, usually within two months of treatment initiation, and can be repeated thereafter, usually in mild to moderate form. All hallucinations disappear during or at the end of treatment, with the vast majority disappearing during treatment and less than 1% of patients having their lives interrupted or discontinuing treatment due to hallucinations. There is also bradycardia, which occurs in about 3.3% of patients, especially during the first 2-3 months of treatment, and in 0.5% of patients with severe bradycardia. Other patients develop atrial fibrillation, headache, blurred vision and poor blood pressure control. Therefore, it is important to keep an eye on the drug during its administration and to seek medical attention for any abnormal manifestations.