Letermovir
Letermovir (Prevymis) is an antiviral medicine used to prevent cytomegalovirus (CMV) infection and disease in certain transplant patients.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
📖 Letermovir: Patient Information Guide
A plain-language walkthrough of Letermovir — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Prevymis (letermovir) is an antiviral medicine approved to prevent CMV (cytomegalovirus) in specific groups of transplant patients.
- Stem cell transplant (HSCT) recipients: Prevymis is approved to prevent CMV infection and disease in adults and children 6 months of age and older, weighing at least 6 kg, who received a stem cell transplant from a donor and who themselves carry the CMV virus (CMV-seropositive).
- Kidney transplant recipients: Prevymis is approved to prevent CMV disease in adults and children 12 years of age and older, weighing at least 40 kg, who received a kidney transplant and are at high risk — meaning the donor tested CMV-positive and the recipient tested CMV-negative (D+/R-).
⚙️How it works▾
Letermovir works by blocking a viral protein complex called the CMV DNA terminase complex. This complex is essential for the cytomegalovirus to cut and package its DNA into new viral particles. Without this step, the virus cannot make functional copies of itself and spread through the body. Because this target is specific to CMV and not found in human cells, letermovir can attack the virus without using the same mechanism as older antivirals.
💊How it's taken▾
Prevymis is taken once daily, by mouth or by IV infusion, depending on which form your care team prescribes. Tablets can be taken with or without food and must be swallowed whole. Oral pellets are mixed with soft food or administered through a feeding tube. The IV infusion is given over one hour in a clinical setting and is reserved for patients who cannot take oral medication.
- For stem cell transplant patients, treatment is typically started between the day of transplant and Day 28, and continued through Day 100 — or up to Day 200 for those at higher risk of late CMV reactivation.
- For kidney transplant patients, treatment starts between Day 0 and Day 7 after transplant and continues through Day 200.
- If you also take cyclosporine, your dose of Prevymis will be adjusted — do not change your dose on your own.
🤒Side effects — in detail▾
The most commonly reported side effects during clinical trials include:
- Nausea
- Diarrhea
- Vomiting
- Swelling in the legs or feet (peripheral edema)
- Cough
- Headache
- Fatigue
- Abdominal pain
A higher rate of cardiac events such as rapid heartbeat (tachycardia) and atrial fibrillation was seen in Prevymis-treated stem cell transplant patients compared to placebo — though most were mild to moderate. Let your care team know right away if you experience a fast or irregular heartbeat, difficulty breathing, severe allergic reaction, or unusual muscle pain or weakness.
⚠️Warnings & precautions▾
- Drug interactions are the biggest concern. Prevymis affects and is affected by many medications commonly used in transplant care. Some combinations are prohibited entirely (pimozide, ergot alkaloids, and certain statins with cyclosporine). Others require close monitoring or dose changes. Your full medication list must be reviewed before and throughout treatment.
- IV form contains hydroxypropyl betadex. This inactive ingredient can accumulate in patients with reduced kidney function. Animal studies have shown it may affect hearing. The IV form should only be used when oral treatment is not possible, and for no longer than 4 weeks if avoidable. Kidney function should be monitored closely in patients with significant renal impairment using the IV form.
- Severe liver disease: Prevymis is not recommended for patients with severe hepatic (liver) impairment.
🔀What it interacts with▾
Prevymis has a wide range of significant drug interactions — always share your full medication list with your prescriber and pharmacist before starting.
- Pimozide: Contraindicated — Prevymis raises pimozide levels, risking dangerous heart rhythm problems (QT prolongation, torsades de pointes).
- Ergot alkaloids (ergotamine, dihydroergotamine): Contraindicated — Prevymis raises their levels, risking ergotism (severe, dangerous blood vessel spasm).
- Pitavastatin and simvastatin + cyclosporine: Contraindicated — the combination dramatically raises statin levels, risking serious muscle damage (myopathy or rhabdomyolysis).
- Cyclosporine: Raises letermovir levels significantly; a lower Prevymis dose is required when these are taken together.
- Other statins (atorvastatin, fluvastatin, lovastatin, pravastatin, rosuvastatin): Prevymis increases their levels; dose limits or reductions apply; monitor for muscle pain.
- Tacrolimus and sirolimus (transplant immunosuppressants): Prevymis raises blood levels; frequent monitoring and dose adjustment of these drugs are needed.
- Warfarin: Prevymis lowers warfarin levels; monitor INR closely to maintain anticoagulation.
- Carbamazepine, phenobarbital, phenytoin, rifampin, rifabutin, nafcillin, St. John's Wort, efavirenz, etravirine, nevirapine, bosentan, modafinil, thioridazine: These can reduce Prevymis levels, potentially making it less effective; co-use is generally not recommended.
- Antidiabetic agents (glyburide, repaglinide, rosiglitazone): Prevymis may raise their levels; monitor blood glucose closely.
- Proton pump inhibitors (omeprazole, pantoprazole): Prevymis may lower their levels; clinical monitoring may be needed.
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- Current medications: Tell your prescriber about every drug, supplement, and herbal product you take — the interaction list for Prevymis is long and includes common transplant medications.
- Kidney problems: If you have reduced kidney function and will use the IV form, your care team must monitor your kidney function closely due to buildup of the IV vehicle (hydroxypropyl betadex).
- Liver problems: Prevymis is not recommended for patients with severe hepatic impairment (Child-Pugh Class C). No dose adjustment is needed for mild or moderate liver disease.
- Pregnancy: Animal studies showed potential harm to fetuses; the risk to human pregnancies is not fully known. Discuss with your doctor if you are pregnant or planning to become pregnant.
- Breastfeeding: It is not known if letermovir passes into human breast milk. Weigh the benefits of breastfeeding against potential risks with your doctor.
- Children: Prevymis is approved for stem cell transplant recipients as young as 6 months (weighing at least 6 kg), but is not established for kidney transplant patients under 12 years old or under 40 kg.
- Older adults: No dose adjustment is needed based on age alone; safety and efficacy were similar across age groups in clinical trials.
🚑If you take too much▾
There is no specific antidote for a Prevymis overdose. If too much is taken, medical staff will monitor for side effects and provide supportive treatment as needed. It is not known whether dialysis can meaningfully remove letermovir from the body.
📡Pharmacodynamics — effects in the body▾
In a dedicated cardiac safety study in healthy adults, letermovir at the approved IV dose — and even at twice that dose — did not cause clinically meaningful prolongation of the QTc interval (the heart's electrical recovery time). This means Prevymis itself is not expected to directly affect heart rhythm in the way some other drugs can, though cardiac monitoring is still recommended given the complexity of the patient population.
🔬Pharmacokinetics — how your body processes it▾
After an oral dose, letermovir is absorbed relatively quickly, with peak blood levels reached within about 1.5 to 3 hours. Food does not meaningfully change the total amount absorbed (though it can modestly increase the peak level), so tablets can be taken with or without a meal. Letermovir is very heavily bound to proteins in the blood (about 99%) and is eliminated primarily through the liver; about 93% of a dose leaves the body through the feces. The drug has a half-life of roughly 12 hours, and steady blood levels are reached after about 9 to 10 days. Oral bioavailability (how much of the drug reaches the bloodstream) varies by patient population and whether cyclosporine is used at the same time — cyclosporine significantly increases letermovir exposure, which is why a dose adjustment is required.
📦How to store it▾
Store PREVYMIS tablets in the original package until use to protect from moisture. Store PREVYMIS tablets at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) .
📄 Written from Letermovir’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Letermovir — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly is Prevymis being used for in my situation? ▾
Can I take my tablet with food, or does it need to be on an empty stomach? ▾
What side effects should I expect, and when should I call my doctor? ▾
I'm on several other medications for my transplant. Is that a problem with Prevymis? ▾
I'm getting the IV form in the hospital. Is that the same as the pill? ▾
Is Prevymis safe during pregnancy? ▾
Is Letermovir available over the counter? ▾
When was Letermovir first available? ▾
Who makes Letermovir? ▾
💬 Answers drafted from Letermovir’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
💊 How Letermovir comes
Letermovir is available in 3 forms. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Injection
How this form is used
- Prevymis injection is used to prevent CMV infection and disease in eligible stem cell transplant recipients who cannot take oral medication
- Prevymis injection is used to prevent CMV disease in eligible high-risk kidney transplant recipients who cannot take oral medication
- Prevymis injection must be diluted before use and administered as an intravenous (IV) infusion over exactly one hour — it must not be given as a rapid bolus injection
- Prevymis injection must be given through a sterile 0.2 or 0.22 micron polyethersulfone (PES) in-line filter via a peripheral or central venous line
- Prevymis injection should only be used in patients unable to take oral therapy; switch to oral Prevymis as soon as possible, ideally limiting IV use to no more than 4 weeks
- Do not use Prevymis injection with IV bags or infusion sets containing the plasticizer DEHP
Tablet
How this form is used
- Prevymis tablets are used to prevent CMV infection and disease in eligible stem cell transplant recipients
- Prevymis tablets are used to prevent CMV disease in eligible high-risk kidney transplant recipients
- Prevymis tablets may be taken with or without food
- Prevymis tablets should be swallowed whole — do not crush or chew
- Prevymis tablets are taken once daily; follow your prescriber's instructions for how long to continue
- Prevymis tablets are not recommended for pediatric patients weighing less than 7.5 kg
Other oral form
How this form is used
- Prevymis oral pellets are used to prevent CMV infection and disease in eligible stem cell transplant recipients, including younger children and those who cannot swallow tablets
- Prevymis oral pellets are used to prevent CMV disease in eligible high-risk kidney transplant recipients who cannot swallow tablets
- Prevymis oral pellets should be mixed with soft food or given through a nasogastric (NG) or gastric (G) tube — do not crush or chew the pellets
- Prevymis oral pellets are taken once daily; follow your prescriber's specific weight-based dosing instructions
- Follow the Instructions for Use provided with Prevymis oral pellets for correct preparation and administration
- Prevymis oral pellets are available in 20 mg and 120 mg packet sizes to allow weight-based dosing in pediatric patients
📊 Letermovir across the U.S. market
How Letermovir appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
FDA-listed product records by dose form (tablet variants merged) — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
Also listed with the FDA, not a patient dose form: Powder (3) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
📈 How widely Letermovir is used
A general measure of how commonly Letermovir is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Letermovir is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Letermovir prescribed? Of the 1,597 medications we measure, Letermovir ranks #1,062 by Medicaid prescriptions — more than 34% of them.
Utilization by Letermovir product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
letermovir 480 MG Oral Tablet Most dispensed
Summed across the 2 of 5 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1988673
letermovir 240 MG Oral Tablet
Summed across the 2 of 5 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1988666
letermovir 120 MG Oral Pellet
Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2693191
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Letermovir, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 5 of 12 listed Letermovir NDCs with Medicaid activity.
🔍 Compare Letermovir products
A representative set of FDA-listed product records for Letermovir — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Injection | ||||
| 1 kg/kg | — | Honour Lab Limited | BULK INGREDIENT | View NDC → |
| 20 mg/mL | Intravenous | Merck Sharp & Dohme LLC × 6 listings | NDA | View NDC → |
| 20 mg/mL | — | MSD Ireland (Carlow) | DRUG FOR FURTHER PROCESSING | View NDC → |
| 💊Other oral form | ||||
| 20 mg | Oral | Merck Sharp & Dohme LLC | NDA | View NDC → |
| 120 mg | Oral | Merck Sharp & Dohme LLC | NDA | View NDC → |
| 💊Tablet | ||||
| 240 mg | Oral | Merck Sharp & Dohme LLC × 3 listings | NDA | View NDC → |
| 480 mg | Oral | Merck Sharp & Dohme LLC × 3 listings | NDA | View NDC → |
| 240 mg | — | MSD International GmbH | DRUG FOR FURTHER PROCESSING | View NDC → |
| 480 mg | — | MSD International GmbH | DRUG FOR FURTHER PROCESSING | View NDC → |
| 💊Bulk drug substance | ||||
| 1 kg/kg | — | MSN Life Sciences Private Limited | BULK INGREDIENT | View NDC → |
| 1 kg/kg | — | Nantong Jinghua Pharmaceutical Co., Ltd | BULK INGREDIENT | View NDC → |
| 1 kg/kg | — | Shandong Chenghui Shuangda Pharmaceutical Co., Ltd. | BULK INGREDIENT | View NDC → |
Showing 21 of 21 products — FDA National Drug Code Directory. See every product, package size and price: browse all 21 Letermovir NDCs →
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Letermovir — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Letermovir in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How Letermovir went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 1988648 3 dose forms · 6 strengths
-
Dose form (SCDF) Injection RxCUI 1988651In current FDA listingsClinical drug / strength (SCD) 12 ML letermovir 20 MG/MLRxCUI 198865224 ML letermovir 20 MG/MLRxCUI 1988660 -
Dose form (SCDF) Oral Pellet RxCUI 2693184In current FDA listings -
Dose form (SCDF) Oral Tablet RxCUI 1988665In current FDA listings
Look up RxCUI 1988648 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
📦 Supply & shortage status
Whether Letermovir is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
Letermovir belongs to the Cytomegalovirus DNA Terminase Complex Inhibitor class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 1 FDA-filed SPL label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
For canonical ingredient pages, bounded product-attributed indication and administration excerpts may be added to the AI evidence, and the generator is instructed to preserve available product, brand, route, and form qualifiers instead of treating one label as universal. Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Merck Sharp & Dohme LLC is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.