For patients who have already had a cerebral infarction, i.e., in terms of secondary prevention of cerebral infarction, long-term medications are required. Antiplatelet agents In patients with TIA of atherosclerotic thrombotic origin, antiplatelet agents are specific for the prevention of recurrent stroke. Studies have shown that three different antiplatelet agents are effective in stroke and/or other vascular disease prevention. (1) Aspirin is the most economical and commonly used antiplatelet drug for stroke prevention and treatment. He acts by interfering with the cyclooxygenase pathway during platelet activation. A meta-analysis of 145 studies including 51,144 patients receiving antiplatelet therapy found that aspirin reduced the risk of stroke by 25%. Aspirin doses between 160-325 mg/d have the broadest antiplatelet efficacy and may be the most beneficial dose.The FDA advocates a dose of 50-325 mg/d of aspirin for stroke prevention. The major side effects of aspirin are gastrointestinal toxicity and bleeding, which are dose-related. However, low doses of aspirin (e.g., 50-70 mg/d) also carry an increased risk of bleeding, especially gastrointestinal bleeding. For patients who cannot tolerate 325 mg due to dyspepsia, measures such as taking it with meals, using enteric-coated tablets, or low-dose aspirin may be used. (2) Clopidogrel Clopidogrel inhibits platelet aggregation induced by ADP, and the CAPRIE trial comparing clopidogrel with aspirin confirmed that clopidogrel was slightly superior to aspirin in preventing vascular events in patients with AT. In high-risk patients with a history of previous ischemic stroke or myocardial infarction, diabetes mellitus, and those receiving lipid-lowering therapy, Polivir should be preferred for secondary prevention of stroke. Recommended dose: clopidogrel 75mg/d. More common side effects are diarrhea and rash, with less bone marrow toxicity. (3) Dipyridamole and aspirin Theoretically, the combination of aspirin, a cyclooxygenase inhibitor, and dipyridamole, a cyclic nucleotide phosphodiesterase inhibitor, is pharmacologically superior to any single drug of the two. Studies have also confirmed that the combination of aspirin and dipyridamole (225 mg/d) resulted in a 37% reduction in the risk of stroke, which was significantly higher than the 18% reduction in the aspirin-only group (25 mgBid) and the 16% reduction in the dipyridamole extended-release (200 mgBid). The combination of aspirin and dipyridamole extended-release was well tolerated and provides another option for stroke prevention. Lipid-lowering drugs Statins for secondary prevention of stroke – The SPARCL study provides strong evidence for statin prevention of stroke recurrence and reinforces the position of statins in secondary prevention of stroke in the guidelines. The Chinese guidelines classify secondary prevention of stroke into 3 tiers: ① Very high risk I, i.e., patients with ischemic stroke/TIA and evidence of arterio-arterial embolism, or evidence of cerebral atherosclerosis-prone plaques, start statin therapy immediately, using an intensive lipid-lowering dose. To reduce LDL-C to 2.1 mmol/L (80 mg/dl) or LDL-C reduction >40%; ② Very high risk II, i.e., those who have ischemic stroke/TIA with coronary artery disease, diabetes mellitus, inability to quit smoking, or one of the metabolic syndromes, the use of statin is to be based on the plasma cholesterol level, and when the LDL-C is >2.1 mmol/L (80 mg/dl), then the use of Statin should be started when LDL-C>2.1mmol/L(80mg/dl), and the dose and target value should be the same as that of very high risk I; ③ All other ischemic stroke/TIA patients are high risk patients, and statin should be started when the LDL-C level is >2.6mmol/L(100mg/dl), using the standard lipid-lowering dose to reduce the LDL-C by 30-40%, such as with Lipitor, i.e., 10-20 mg, and the target value of LDL-C should be <2.6mmol/L(100mg/dl). mmol/L (100mg/dl). Anticoagulants (1) Effects on cardiac stroke Atrial fibrillation (AF) is the most common cause of cardiac stroke, and 10% to 20% of patients with AF will have a serious disabling stroke in the future course of their disease. Warfarin is a dose-adjustable oral anticoagulant for ischemic stroke patients with atrial fibrillation. Studies have shown that anticoagulants are superior to aspirin for prevention in patients with atrial fibrillation and recent TIAs and mini-strokes. Aspirin therapy is recommended for patients with cardiogenic embolism who are also contraindicated for oral anticoagulants. Regarding the optimal intensity of anticoagulation, recent studies have found that the efficacy of oral anticoagulants decreases significantly when the INR (intemationalnormalizedratio) is lower than 2.0.The target value of the INR is 2.5 (2.0~3.0) as a suitable indicator for anticoagulation. (2) Effect on atherothrombotic stroke There is not enough evidence to prove the effect of anticoagulants on atherothrombotic stroke. Some experts also recommend anticoagulation for patients taking antiplatelet agents who develop TIA, and for patients with progressively worsening TIA. Patients with extracranial carotid artery dissection, severe carotid stenosis prior to endarterectomy, antiphospholipid antibody syndrome, or cerebral venous sinus thrombosis may support anticoagulation.