What are the precautions for Letermovir?

Letermovir is a prescription antiviral drug that is used to help prevent cytomegalovirus (CMV) infection and disease in people who have received a stem cell transplant or a kidney transplant and who are at high risk for CMV disease. In clinical studies, warnings and precautions such as the risk of adverse reactions or reduced efficacy due to drug interactions and risks related to the excipients of hydroxypropyl betadex in intravenous preparations have emerged. Discontinue and resume at reduced dose upon recovery, or permanently discontinue based on severity.

1. Risk of adverse reactions or reduced efficacy due to drug interactions

Combining letermovir with certain drugs may result in potentially significant drug interactions, some of which may result in adverse reactions(letermoviror the concomitant drug) or a reduction in the therapeutic effect of letermovir or the concomitant drug. Consider the potential for drug interactions before and during previral therapy; review concomitant medications during HIV prophylaxis treatment; and concomitant medication-related adverse effects.

2. Risks related to hydroxypropyl betadex excipients in intravenous preparations

Intravenous formulations of letermovir contain the excipient hydroxypropyl betaide. Letermovir injection should be used only in patients who are unable to receive oral therapy and should be switched to oral letermovir as soon as the patient is able to receive oral medication. If possible, intravenous administration should not exceed4 weeks. Accumulation of hydroxypropylbetadide may occur in patients with renal impairment. Serum creatinine levels should be monitored closely in adult patients with a CLcr less than 50 mL/min and in pediatric patients with similar renal impairment receiving letermovir injection (based on age-appropriate renal function assessment). Animal studies have shown that hydroxypropyl betadex may cause ototoxicity. The active ingredient letermovir is not associated with ototoxicity.

Reference materials:https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1b49df80-be4f-47e0-a0b7-123f3e69395b