Letimovir is a cell proliferation virus terminal transferase inhibitor that inhibits the activity of CMV DNA terminal enzyme complexes (including pUL51, pUL56, and pUL89), blocking CMV DNA replication and suppressing virus proliferation.

1、 Drug name

1. Common name: Letermovir;

2. Product Name: PREVYMIS ®。

2、 Indications

1. Prevention of CMV infection after hematopoietic stem cell transplantation (HSCT): Suitable for CMV seropositive receptors (R+) aged 6 months and above with a body weight of ≥ 6kg.

2. Prevention of CMV disease after kidney transplantation: Suitable for high-risk (D+/R -) recipients aged 12 years and above with a body weight of ≥ 40kg.

3、 Specifications and characteristics

Tablets: 240mg

4、 Main components

1. Active ingredient: Letimovir;

2. The excipients include microcrystalline cellulose, cross-linked carboxymethyl cellulose sodium, etc. The injection contains hydroxypropyl betacyclodextrin.

5、 Usage and dosage

1. HSCT receptor:

Adults and children aged 12 years or older: 480mg orally or intravenously once daily (1 hour) for 100 days after transplantation; For high-risk individuals, the extension can be up to 200 days.

Children aged 6 months to<12 years: Adjust the dosage according to body weight (e.g. 480mg for ≥ 30kg; 80mg for 6-<7.5kg).

2. Renal transplant recipient:

480mg once daily, lasting for 200 days after transplantation.

6、 Dose adjustment

1. Combined with cyclosporine:

Reduce the dosage to 240mg/day for adults and children aged 12 and above; Children under 12 years old need individualized adjustment.

2. Kidney/liver dysfunction:

When administering intravenous medication for renal injury (CLcr<50mL/min), creatinine should be monitored; Severe liver damage (Child Pugh C grade) is contraindicated.

7、 Medication precautions

1. Medication time: Tablets can be taken with food or on an empty stomach; Oral granules should be taken within 10 minutes after mixing with room temperature soft food.

2. Omission treatment: Take the medication immediately, skip if it is close to the next dose time, and do not double the dose.

3. Vomiting treatment: If vomiting occurs after taking the medication, there is no need to take it again. Continue with the next dose according to the original plan.

4. Injection restriction: Only for those who cannot take it orally. It is recommended to administer it intravenously for ≤ 4 weeks.

8、 Medication for special populations

1. Children: HSCT recipients aged ≥ 6 months or renal transplant recipients aged ≥ 12 years are available and should be administered strictly according to body weight.

2. Pregnancy/lactation: No human data available, animals show reproductive toxicity, weighing the pros and cons.

3. Elderly: No need to adjust dosage.

9、 Adverse reactions

1. HSCT receptors: common nausea (27%), diarrhea (26%), vomiting (19%), peripheral edema (14%).

2. Renal transplant recipients: Diarrhea (32%) is the main adverse reaction.

10、 Contraindications

1. Prohibition of combined use of pimozide and ergot alkaloids.

2. When used in combination with cyclosporine, pravastatin and simvastatin are contraindicated.

11、 Drug interactions

1. CYP3A inhibitors/inducers, such as rifampicin and carbamazepine, may reduce the efficacy of letamivir and should be avoided in combination.

2. Statins: Atorvastatin dosage ≤ 20mg/day when combined with cyclosporine.

12、 Storage method

Tablets: Store in the original packaging away from moisture at room temperature (20-25 ℃).

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