Lecanemab (Leqembi) must be used under professional medical guidance. Adherence to prescribed medication and a healthy lifestyle can better ensure treatment efficacy and safety.

I. Dosage and Administration

1. Pre-treatment Preparation

(1) Before initiating treatment, the presence of brain β-amyloid pathology must be confirmed (via PET or cerebrospinal fluid testing), and a recent baseline brain MRI must be obtained.

(2) ApoEε4 genotyping should also be performed to assess the risk of ARIA.

2. Starting Dose (Intravenous Infusion)

(1) The recommended starting dose is 10 mg/kg administered every two weeks.

(2) Before each infusion, the drug must be diluted in 250 mL of 0.9% sodium chloride injection and administered intravenously over approximately 1 hour through an infusion line equipped with a 0.2-micron filter.

3. Maintenance Dose (Optional after 18 months)

(1) After completing 18 months of starting therapy, treatment may continue with the original regimen or be switched to one of the following maintenance regimens:

(2) Intravenous infusion: 10 mg/kg every 4 weeks.

(3) Subcutaneous injection: Using the LEQEMBI IQLIK autoinjector, 360 mg once weekly.

4. Route Conversion

(1) During maintenance therapy, switching between intravenous and subcutaneous regimens is allowed.

(2) When switching, the new regimen should be initiated 1 week after the last maintenance dose.

5. Missed Dose Management

(1) Intravenous infusion: Administer the missed dose as soon as possible.

(2) Subcutaneous injection: If a dose is missed, it can be administered within 6 days; after that, resume the original schedule. If more than 6 days have passed, skip the missed dose.

II. Medication Precautions

1. ARIA Monitoring and Dose Adjustment

During treatment, repeat MRI scans should be performed within one week before the 3rd, 5th, 7th, and 14th infusions. If ARIA occurs, decide whether to temporarily discontinue the drug based on the type, radiographic severity, and clinical symptoms:

(1) Asymptomatic mild-to-moderate ARIA-E may continue treatment.

(2) Moderate-to-severe or symptomatic ARIA-E requires temporary discontinuation, with repeat MRI after 2-4 months to confirm resolution before reassessing restart.

(3) ARIA-H or intracerebral hemorrhage >1 cm requires temporary discontinuation; after stabilization, the clinician determines whether to resume.

2. Infusion Reaction Prevention

(1) Infusion reactions are most common during the first infusion (accounting for 75% of all infusion reactions).

(2) If fever, chills, nausea, etc. occur, the infusion rate may be slowed or stopped, and symptomatic treatment given.

(3) Prophylactic use of antihistamines, acetaminophen, or corticosteroids may be considered before subsequent infusions.

3. Bleeding Risk Warning

(1) Patients taking anticoagulants (e.g., warfarin, apixaban) have a significantly increased risk of intracerebral hemorrhage; a careful benefit-risk assessment is required.

(2) If sudden severe headache, nausea/vomiting, altered consciousness, or limb weakness occurs, seek immediate emergency medical attention.

4. Allergy and Contraindications

(1) Severe hypersensitivity to any component of this product is contraindicated.

(2) If angioedema (swelling of face, lips, tongue) or difficulty breathing occurs, discontinue the drug immediately and provide emergency management.

5. Use in Special Populations

(1) Pregnancy/Breastfeeding: Safety data are lacking; use only if the potential benefit outweighs the risk.

(2) Children: Not applicable.

(3) Elderly: No dose adjustment is needed.

(4) Hepatic/Renal impairment: No study data available, but monoclonal antibodies are not expected to be metabolized by the liver or kidneys.

III. Healthy Lifestyle for Patients

1. Regular Follow-up and MRI Monitoring

(1) Strictly adhere to scheduled periodic MRI and cognitive function assessments to detect and manage ARIA early.

(2) If headache, vision changes, confusion, seizures, or limb weakness occur, contact a physician immediately.

2. Manage Underlying Diseases Appropriately

(1) Controlling risk factors for cerebrovascular disease such as hypertension, diabetes, and hyperlipidemia may help reduce the risk of intracerebral hemorrhage.

(2) If antiplatelet agents (e.g., aspirin) or anticoagulants are needed, be sure to inform your neurologist.

3. Cognitive and Functional Exercise

Under medical guidance, engage in cognitive training (e.g., memory and attention exercises) and moderate physical activities (e.g., walking, tai chi) to help maintain cognitive function and daily living abilities.