Letermovir (Oral)

Letermovir is used by itself or with another medicine (for example, cyclosporine) to stop cytomegalovirus (CMV) infection and disease in patients who have had an allogeneic hematopoietic stem cell (bone marrow) transplant or in patients who have had a kidney transplant and are at high risk for getting CMV disease.

This medicine is available only with your doctor's prescription.

It is very important that your doctor checks your progress at regular visits to ensure that this medicine is working properly and to monitor for unwanted effects.

Do not use this medicine together with pimozide (Orap®) or ergot medicines (for example, dihydroergotamine, ergonovine, ergotamine, methylergonovine, Cafergot®, Ergomar®, Wigraine®).

Do not use pitavastatin (Livalo®) or simvastatin (Zocor®) when you take this medicine along with cyclosporine (Gengraf®, Neoral®, Sandimmune®).

Do not stop taking this medicine without consulting your doctor first.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

In deciding to use a medicine, you and your doctor need to consider the risks of taking the medicine versus the benefits it will provide. The following points should be taken into account for this medicine:

Allergies

Inform your doctor if you have ever had any unusual or allergic reactions to this medicine or any other medicines. Also, let your healthcare professional know about any other allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

There have not been appropriate studies on how letermovir affects children. Its safety and effectiveness in children have not been established.

Geriatric

Current studies have not shown geriatric-specific problems that would limit the usefulness of letermovir in older adults.

Breast Feeding

There are no adequate studies in women to determine the risk to infants when using this medication during breastfeeding. Consider the potential benefits and risks of taking this medication while breastfeeding.

Interactions with Medicines

Some medicines should never be used together, while others can be used together even if an interaction might happen. In cases where two medicines are used together, your doctor may adjust the dose or take other precautions. When taking this medicine, it is very important that your healthcare professional knows if you are using any of the following medicines. The interactions listed below are selected for their potential significance and are not all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

• Bromocriptine
• Dihydroergotamine
• Eliglustat
• Ergonovine
• Ergotamine
• Flibanserin
• Lomitapide
• Methylergonovine
• Methysergide
• Pimozide
• Pitavastatin
• Simvastatin

Using this medicine with any of the following medicines is usually not recommended, but may be necessary in some cases. If both medicines are prescribed together, your doctor may adjust the dose or frequency of use for one or both medicines.

• Acalabrutinib
• Alprazolam
• Amiodarone
• Aprepitant
• Atorvastatin
• Avapritinib
• Bosutinib
• Brexpiprazole
• Brigatinib
• Buprenorphine
• Cilostazol
• Clozapine
• Cobimetinib
• Codeine
• Colchicine
• Cyclosporine
• Daridorexant
• Darolutamide
• Deflazacort
• Elacestrant
• Elexacaftor
• Enasidenib
• Encorafenib
• Entrectinib
• Eplerenone
• Fexinidazole
• Finerenone
• Fosaprepitant
• Fosphenytoin
• Gepirone
• Glyburide
• Ibrutinib
• Infigratinib
• Ivabradine
• Ivacaftor
• Ivosidenib
• Larotrectinib
• Leflunomide
• Lemborexant
• Leniolisib
• Lovastatin
• Lumateperone
• Lurasidone
• Lurbinectedin
• Mavacamten
• Midazolam
• Midostaurin
• Mitapivat
• Mobocertinib
• Naloxegol
• Olaparib
• Omaveloxolone
• Oxycodone
• Pacritinib
• Palovarotene
• Pemigatinib
• Pexidartinib
• Phenytoin
• Pralsetinib
• Repaglinide
• Rifampin
• Rimegepant
• Rosiglitazone
• Selpercatinib
• Selumetinib
• Sirolimus
• Sirolimus Protein-Bound
• Sonidegib
• Sparsentan
• Tacrolimus
• Tazemetostat
• Teriflunomide
• Tezacaftor
• Tolvaptan
• Trofinetide
• Ubrogepant
• Venetoclax
• Venlafaxine
• Voclosporin
• Voriconazole
• Warfarin
• Zanubrutinib
• Zolpidem

Using this medicine with any of the following medicines may increase the risk of certain side effects, but it might be necessary to use both for your treatment. If both medicines are prescribed together, your doctor may adjust the dose or frequency of use for one or both medicines.

• Amlodipine
• Eltrombopag
• Suvorexant

Interactions with Food/Tobacco/Alcohol

Some medicines should not be taken around mealtime or with certain types of food because interactions may occur. Using alcohol or tobacco with certain medicines may also lead to interactions. Discuss with your healthcare professional about using your medicine with food, alcohol, or tobacco.

Other Medical Problems

Having other medical issues may affect the use of this medicine. Be sure to inform your doctor if you have any other medical problems, especially:

• Kidney disease, severe—Use with caution. May worsen this condition.

• Liver disease, severe—Use is not recommended for patients with this condition.

Along with its necessary effects, a medicine may cause some unwanted effects. Not all of these side effects may happen, but if they do, they may need medical attention.

Check with your doctor right away if any of the following side effects occur:

More common

• Bloating or swelling of the face, arms, hands, lower legs, or feet
• rapid weight gain
• tingling of the hands or feet
• unusual weight gain or loss

Less common

• Black, tarry stools
• chest pain
• chills
• cough
• dizziness
• fainting
• fast, pounding, or irregular heartbeat or pulse
• fever
• lower back or side pain
• painful or difficult urination
• pale skin
• sore throat
• trouble breathing
• ulcers, sores, or white spots in the mouth
• unusual bleeding or bruising
• unusual tiredness or weakness

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue, are bothersome, or if you have any questions about them:

More common

• Diarrhea
• headache
• nausea
• stomach pain
• vomiting

Other side effects not listed may also happen in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

In the U.S.

• Prevymis

Available Dosage Forms:

• Tablet

Therapeutic Class: Antiviral

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

This medicine should come with a patient information leaflet. Read and follow these instructions carefully. Ask your doctor if you have questions.

You may take this medicine with or without food.

Swallow the tablet whole. Do not crush, break, or chew it.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage form (tablets): For prevention of CMV infection or disease in patients who have received hematopoietic stem cell transplant: Adults—480 milligrams (mg) once a day, starting between Day 0 and Day 28, and continue until Day 100 after transplant. Children—Use and dose must be determined by your doctor. For prevention of CMV infection or disease in patients who have received kidney transplant: Adults—480 milligrams (mg) once a day, starting between Day 0 and Day 7, and continue until Day 200 after transplant. Children—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Store the medicine in its original container until you are ready to use it.