Letermovir taken with meals can improve tolerance, and when combined with cyclosporine, the dose should be halved (240mg). For patients with renal insufficiency, the dose should be reduced according to CrCl. All adjustments must be made under the guidance of a physician and cannot be changed by oneself.

1、 Fasting or with meals?

It can be taken with meals or on an empty stomach, but to reduce gastrointestinal discomfort, it is recommended to take it with meals.

Take medication at a fixed time every day to maintain consistency.

Swallow the tablet as a whole and do not crush or chew it; Shake the suspension thoroughly before use.

2、 Dose adjustment for combined administration with cyclosporine

2.1 Standard Dose

Normal renal function (CrCl ≥ 60mL/min) and no use of cyclosporine: 480mg, once daily (tablet or suspension).

2.2 When combined with cyclosporine

Cyclosporine can significantly increase the blood concentration of letamivir, therefore the dosage is halved when used in combination:

240mg， Once a day.

If cyclosporine is discontinued in the future, it should be restored to 480mg once a day.

After dose adjustment, patient tolerance needs to be observed, but no additional blood drug concentration monitoring is required.

3、 Dose adjustment during renal insufficiency (including cyclosporine combination)

CrCl ≥ 60mL/min: 480mg (reduced to 240mg when combined with cyclosporine).

CrCl 30-59mL/min: 480mg (reduced to 240mg when combined with cyclosporine).

CrCl10～29mL/min：240mg， Once daily (whether or not combined with cyclosporine).

CrCl<10mL/min or dialysis: Not recommended for use, or only for those with clear benefits outweighing risks.

4、 Other important precautions

Missing service handling: If the missed service time is less than 12 hours, replace it as soon as possible; If ≥ 12 hours, skip this dose and take according to the original plan the next day.

Avoid combining with Pimozide and ergot alkaloids as there is a significant risk of interaction.

When used in combination with tacrolimus, there is no need to adjust the dose of letamivir, but the blood concentration of tacrolimus needs to be monitored.