Prevymis Shortage Update: What Patients Need to Know in 2026

If you've had trouble filling your Prevymis (letermovir) prescription, you may be wondering: Is there a shortage? Is Merck having production problems? Or is something else going on? Here is everything transplant patients need to know about Prevymis availability in 2026.

Is Prevymis Currently on a Drug Shortage List?

As of 2026, Prevymis (letermovir) is not listed on the FDA's official drug shortage database. Merck, the manufacturer, has not issued any shortage notices for this medication. The drug continues to be manufactured and distributed in both tablet and IV injection forms.

However, many transplant patients do experience difficulty filling their prescriptions. Understanding why requires knowing how Prevymis reaches patients — and it's not through the same channels as common medications.

Why Do Patients Still Have Trouble Finding Prevymis?

Even when there is no national shortage, patients may face local or logistical availability issues. The main reasons include:

• Specialty pharmacy distribution: Prevymis is dispensed primarily through specialty pharmacies, not standard retail locations. Most neighborhood pharmacies simply don't stock it.
• Insurance prior authorization: Most insurers require prior authorization before covering Prevymis. Delays in PA approval can make the drug temporarily inaccessible.
• High cost barrier: Prevymis costs approximately $8,700 or more per 30-day supply at retail prices. Without insurance coverage or assistance programs, the medication is unaffordable for most patients.
• Low local demand: Because relatively few people in any given area are on Prevymis at one time, even pharmacies that do stock it may run low quickly.

Background: When Did Prevymis Availability Become an Issue?

Since Prevymis was first approved in November 2017, its use has expanded significantly. In 2023, the FDA approved Prevymis for high-risk kidney transplant recipients (D+/R-), broadening the patient population. New pediatric approvals (6 months+ for HSCT, 12 years+ for kidney transplant) were added for oral pellet formulations. Each expanded indication has increased demand for a drug that was already being distributed through limited specialty channels.

This increased demand without a corresponding expansion in retail pharmacy distribution has created growing confusion for patients and caregivers who try to fill Prevymis at standard pharmacies and are told it isn't available.

What Should Patients Do Right Now?

If you are a transplant patient prescribed Prevymis and are having trouble filling your prescription, take these steps immediately:

1. Call your transplant coordinator today. They have experience navigating specialty pharmacy channels and can often resolve the issue within 24-48 hours.
2. Contact the Merck Access Program. Merck provides a dedicated support line to help connect patients with dispensing pharmacies and navigate insurance issues. Call 1-855-257-3932.
3. Try medfinder. medfinder contacts pharmacies near you by phone to find which ones can fill your specific prescription, then texts you the results. This is especially useful when pharmacy inventory systems don't accurately reflect specialty drug stock.
4. Check for IV formulation availability if you're inpatient. If you are hospitalized and oral tablets are unavailable, Prevymis is also available as an IV infusion (240 mg or 480 mg vials). Your hospital pharmacy may have the IV form even if oral tablets are not in stock. No dose adjustment is needed when switching between oral and IV formulations.

What Is the Risk of Delaying Prevymis?

Delaying Prevymis after a transplant is not a safe option. CMV can reactivate rapidly in immunocompromised patients, and any level of CMV infection is associated with increased mortality in HSCT patients. The FDA-approved protocol calls for Prevymis to be started between Day 0 and Day 28 post-transplant and continued through at least Day 100. Any gap in prophylaxis creates a window of vulnerability that can have serious consequences.

Staying Informed About Prevymis Availability

Bookmark the FDA's drug shortage database (accessdata.fda.gov) and check it periodically. Your transplant team also monitors supply issues proactively. If you need immediate help finding Prevymis, see our guide: How to Find Prevymis in Stock Near You.