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

If your patients with overactive bladder (OAB) are calling your office about difficulty filling their Myrbetriq prescriptions, the situation reflects a complex convergence of ongoing patent litigation, evolving insurance step therapy mandates, and pharmacy-level stocking variability — not a traditional FDA-designated drug shortage. This guide provides prescribers with a clear picture of what's happening and how to manage affected patients.

Clinical Summary: Myrbetriq Supply Status in 2026

Brand-name Myrbetriq (mirabegron extended-release, Astellas Pharma) is not listed on the FDA Drug Shortages database as of 2026. Manufacturing and distribution of the brand product remain intact. However, the generic mirabegron market has been significantly disrupted by intellectual property litigation:

• April 2024: A temporary federal injunction halted generic launches from Lupin and Zydus despite their FDA approvals.
• April 2025: A U.S. Federal Court ruling blocked Lupin and Zydus from selling generic mirabegron based on patent infringement grounds. Other approved manufacturers (including Alkem) remain in the market.
• November 2025: UnitedHealthcare implemented a step therapy program requiring commercial plan members to fail two alternative OAB agents before generic mirabegron is covered.

Insurance Landscape: Step Therapy and Prior Authorization

Prescribers should be aware of the following insurance-driven access barriers affecting mirabegron:

• UnitedHealthcare Step Therapy (effective 11/16/2025): Requires documented failure, contraindication, or intolerance to TWO alternative OAB agents before approving generic mirabegron coverage. Exceptions for contraindications or prior therapy should be documented in the chart.
• Prior authorization: Brand-name Myrbetriq typically requires prior authorization at most commercial plans. PAs should document OAB diagnosis, severity, and any contraindications to anticholinergic alternatives.
• Medicare Part D: Coverage varies by plan. Many Part D plans require step therapy with generic anticholinergics first. Prior authorization with documented rationale for avoiding anticholinergics (cognitive risk in elderly, glaucoma contraindication, etc.) can support appeals.

Clinical Context: When to Prescribe Myrbetriq vs. Alternatives

Per AUA/SUFU 2024 OAB guidelines, antimuscarinics and beta-3 agonists (mirabegron, vibegron) are both recommended as pharmacological treatment options following failure of behavioral interventions. Mirabegron is particularly preferred in the following clinical scenarios:

• Older adults (65+) where anticholinergic burden is a concern — mirabegron avoids anticholinergic cognitive risk
• Patients with narrow-angle glaucoma (contraindication to antimuscarinics)
• Patients with urinary retention risk on antimuscarinics (e.g., bladder outlet obstruction, concurrent antimuscarinic use)
• Patients intolerant of dry mouth, constipation, or other anticholinergic side effects
• Patients on multiple CYP2D6-sensitive medications (note: mirabegron IS a moderate CYP2D6 inhibitor — interaction review is required)

Prescribing Tips for Better Access and Fewer Refill Calls

These prescribing practices can reduce access barriers for your patients:

1. Write "generic mirabegron OR brand Myrbetriq" (DAW 0). This allows the pharmacy to dispense whichever form is in stock.
2. Document anticholinergic contraindications in the chart. For step therapy exceptions, insurers need documented evidence of why anticholinergic alternatives were not appropriate.
3. Recommend mail-order pharmacy. Insurance mail-order pharmacies typically maintain steady inventory for maintenance medications.
4. Recommend the Astellas Momentum Savings Card. For commercially insured patients struggling with brand costs, the Momentum Savings Card covers up to $70/month ($840 max/year). The Patient Assistance Program covers brand Myrbetriq at no cost for eligible uninsured patients.
5. Tell patients about medfinder. For patients who encounter local pharmacy stock issues, medfinder is a paid service that calls pharmacies on patients' behalf to locate available stock and texts them results.

Key Drug Interactions to Review Before Prescribing

Mirabegron is a moderate CYP2D6 inhibitor. Clinically significant interactions include:

• Digoxin: Use the lowest digoxin dose; monitor serum digoxin levels and titrate to desired clinical effect
• CYP2D6 substrates with narrow therapeutic index (metoprolol, flecainide, propafenone, thioridazine, desipramine): Monitor for increased drug levels; consider dose adjustment
• Ozanimod: Avoid concurrent use due to risk of hypertensive crisis

Provider Resources

medfinder offers a provider portal to help your patients find Myrbetriq in stock. Also see our guide: How to Help Your Patients Find Myrbetriq In Stock.