Precautions of Letermovir

1. Risk of Adverse Reactions or Reduced Efficacy Due to Drug Interactions

Concomitant use of letermovir tablets with certain drugs may result in potentially significant drug interactions, some of which may lead to adverse reactions or reduce the efficacy of letermovir tablets or the concomitant drug.

2. Risks Associated with the Hydroxypropyl Betadex Excipient in the Intravenous Formulation

The intravenous formulation of letermovir contains the excipient hydroxypropyl betadex. Letermovir injection should be used only in patients who are unable to take oral therapy; once patients are able to take oral medication, they should be switched to oral letermovir tablets. If possible, intravenous administration should not exceed 4 weeks.

Hydroxypropyl betadex may accumulate in patients with renal impairment. In adult patients receiving letermovir injection with creatinine clearance less than 50 mL/min and in pediatric patients with a similar degree of renal impairment, serum creatinine levels should be closely monitored.

Animal studies suggest that hydroxypropyl betadex has the potential to cause ototoxicity. The active ingredient letermovir is not known to be associated with ototoxicity.