Letermovir (oral/injection)

Generic name: letermovir (oral/injection) [ le-TERM-oh-vir ]
Brand name: Prevymis
Dosage forms: intravenous solution (240 mg/12 mL; 480 mg/24 mL), oral pellet (120 mg; 20 mg), oral tablet (240 mg; 480 mg)
Drug class: Miscellaneous antivirals

Medically reviewed by Drugs.com on Apr 29, 2025. Written by Cerner Multum.

What is letermovir?

Letermovir is an antiviral medicine used to help prevent cytomegalovirus (CMV) infection after a stem cell (bone marrow) transplant from a donor in adults and children at least 6 months old and weighing at least 88 pounds (40 kg).

Letermovir is also used to prevent CMV in adults and children at least 6 months old and weighing at least 88 pounds (40 kg) who have received a kidney transplant and are at increased risk of developing a CMV infection.

Your doctor will perform tests to make sure letermovir is the right treatment for you.

Letermovir may also be used for purposes not listed in this medication guide.

Letermovir side effects

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Letermovir may cause serious side effects. Call your doctor at once if you have:

• fast or irregular heartbeats.

Common side effects of letermovir may include:

• nausea, diarrhea, vomiting, stomach pain;

• swelling in your arms or legs;

• cough;

• headache; or

• feeling tired.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Related/similar drugs

Warnings

Tell your doctor about all your current medicines. Many drugs can affect letermovir, and some drugs should not be used together.

Before taking this medicine

Some drugs should not be used with letermovir. Your treatment plan may change if you also use:

• pimozide;

• cholesterol medication--pitavastatin, simvastatin; or

• ergot medicine--dihydroergotamine, ergotamine, ergonovine, methylergonovine.

Tell your doctor if you have ever had:

• diabetes;

• high cholesterol or triglycerides (a type of fat in the blood); or

• liver or kidney disease.

Tell your doctor if you are pregnant or breastfeeding.

How should I use letermovir?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Letermovir oral is taken by mouth once per day with or without food.

Letermovir injection is injected into a vein by a healthcare provider only if you are unable to take medicine by mouth.

Letermovir oral granules are mixed with one to three teaspoons of soft foods such as applesauce, yogurt, or pudding, and the mixed medicine should be taken within 10 minutes. Letermovir oral granules can also be given through a feeding tube. Talk to your doctor or pharmacist if you do not understand these instructions.

Doses are based on weight. Your dose may change if you gain or lose weight.

Your condition may get worse if you stop using letermovir suddenly. Ask your doctor before stopping the medicine.

Do not crush, or chew letermovir oral pellets. Swallow the tablet whole and do not crush, break, or dissolve it.

Store letermovir in the original container at room temperature away from moisture and heat.

Letermovir dosing information

Usual Adult Dose for CMV Prophylaxis:

480 mg orally or IV once a day

Comments:
-The IV formulation should be administered at a constant rate over 1 hour.
-Hematopoietic Stem Cell Transplant (HSCT): This drug should be started between Day 0 and Day 28 post-HSCT (before or after engraftment) and should continue through Day 100 post-HSCT.
---In patients at risk for late CMV infection and disease, this drug may be continued through Day 200 post-HSCT.
-Kidney Transplant: This drug should be started between Day 0 and Day 7 and should continue through Day 200 posttransplant.

Uses:
-For the prophylaxis of CMV infection and disease in CMV-seropositive recipients (R+) of an allogeneic HSCT
-For the prophylaxis of CMV disease in kidney transplant recipients at high risk (donor CMV seropositive/recipient CMV seronegative [D+/R-])

What happens if I miss a dose?

Use the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using letermovir?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect letermovir?

Sometimes it is not safe to use certain medicines at the same time. Some drugs can affect your blood levels of other drugs you use, which may increase side effects or make the medicines less effective.

If you also use cyclosporine, your letermovir dose will need to be adjusted.

Other drugs may affect letermovir, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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