Adefovir Shortage: What Providers and Prescribers Need to Know in 2026

Adefovir dipivoxil (Hepsera) has experienced declining prescription volumes over the past decade as newer, more potent hepatitis B antivirals have taken center stage. While not on the FDA's official Drug Shortage List as of 2026, adefovir's low-demand status means patchy pharmacy stocking — a challenge that falls squarely on prescribers and care teams to manage proactively when patients report difficulties filling their prescriptions.

Current Adefovir Supply Status (2026)

Adefovir dipivoxil is not on the FDA Drug Shortage List or the ASHP Drug Shortage List as of 2026. However, its clinical use has significantly declined as current hepatitis B treatment guidelines (AASLD, EASL) now position entecavir, tenofovir disoproxil fumarate (TDF), and tenofovir alafenamide (TAF) as preferred first-line agents. Adefovir retains a role in:

Patients with lamivudine-resistant HBV who cannot use first-line agents (combination with lamivudine)

Patients with specific contraindications to entecavir, TDF, or TAF

Existing stable patients whose HBV is well-controlled on adefovir and for whom switching carries risk

Why Patients Are Reporting Availability Difficulties

The root cause is straightforward: as adefovir's market share shrinks (estimated -5.8% CAGR, 2023-2028), pharmacies rationalize their inventory. Retail pharmacies stock based on local demand. In most markets, that demand for adefovir is minimal. The practical result is:

Many retail pharmacies carry no adefovir on-hand

Pharmacies that do stock it may have limited quantities (enough for 1-2 patients)

Supply gaps are not coordinated — there is no shortage declaration to trigger emergency protocols

Multiple generic manufacturers create formulary fragmentation: pharmacy A stocks Apotex generic; pharmacy B stocks Sigmapharm generic; insurance may only cover one

Clinical Considerations When Switching Away from Adefovir

If a patient is stable on adefovir but consistently unable to fill their prescription, switching to a more available first-line agent is often clinically appropriate. Key considerations:

Resistance history matters. Review the patient's prior antiviral exposure. Patients who were on adefovir due to lamivudine resistance may have adefovir resistance mutations (rtA181T/V, rtN236T). Tenofovir DF and TAF are active against adefovir-resistant HBV strains and are appropriate alternatives.

Renal function assessment is mandatory before switching to TDF. Patients already on adefovir may have some degree of nephrotoxicity. TDF requires careful baseline and ongoing renal monitoring. TAF is preferred for patients with eGFR impairment due to its improved renal and bone safety profile.

Entecavir is not optimal for lamivudine-resistant patients. If the patient has lamivudine-resistant HBV, entecavir at 1 mg is less effective and carries higher risk of entecavir resistance. TDF or TAF are preferred in this setting.

Concurrent use of adefovir and tenofovir is contraindicated. Do not overlap adefovir and tenofovir DF or TAF at any point during the transition. When switching, the last dose of adefovir and first dose of tenofovir should be sequential, not overlapping.

Monitor hepatic function after switching. Although switching to a more potent agent should not cause flares, monitor liver enzymes and HBV DNA at 1-3 months post-switch to confirm virologic control.

Recommended Alternative Agents for Prescribers

Entecavir (Baraclude/generic): 0.5 mg QD for treatment-naive patients; 1 mg QD for lamivudine-experienced. High genetic barrier to resistance. No nephrotoxicity. Most widely stocked hepatitis B antiviral.

Tenofovir DF (Viread/generic): 300 mg QD. Active against all resistance variants including adefovir-resistant strains. Requires baseline and ongoing renal monitoring. Generic widely available and affordable.

Tenofovir alafenamide (Vemlidy): 25 mg QD. Preferred over TDF for patients with renal insufficiency, osteoporosis, or those at risk of bone/kidney adverse effects. Currently brand-only; prior authorization often required.

39,333+ patients found their medications in stock

39K+

Find Adefovir In Stock Today →

How to Help Patients Find Adefovir If Switching Is Not Indicated

For patients who should stay on adefovir, direct them to medfinder for providers. medfinder calls pharmacies near the patient to identify which ones can fill the prescription today — eliminating the need for your staff or the patient to spend time on hold. You can also direct patients to specialty pharmacies or mail-order pharmacies (90-day supply) to reduce the frequency of this problem.

Proactive Steps for Your Practice

Identify patients currently on adefovir and assess whether transition to first-line agents is clinically appropriate

For those who should remain on adefovir, route prescriptions to specialty or mail-order pharmacies

Counsel patients not to stop adefovir without contacting your office — emphasize the risk of hepatic exacerbation

Consider 90-day fills for stable patients to reduce monthly refill disruptions

See also: How to Help Your Patients Find Adefovir in Stock: A Provider's Guide