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

Basaglar (insulin glargine injection, 100 units/mL) remains in production and available nationally through Eli Lilly as of 2026. However, the broader insulin glargine market has experienced significant disruption following the discontinuation of Semglee (insulin glargine-yfgn) in December 2025 — and a separate Lilly business decision to phase out the Basaglar Tempo Pen by mid-2026. This briefing provides a current clinical overview for providers managing patients on Basaglar.

Current Market Status (Updated 2026)

Per the ASHP Insulin Glargine Shortage Bulletin (updated March 25, 2026), the following is the current insulin glargine landscape:

• Basaglar KwikPen (Eli Lilly): Available — confirmed by Lilly. Good national availability.
• Basaglar Tempo Pen (Eli Lilly): Discontinuing — available through July 27, 2026 only. Proactively transition patients to KwikPen.
• Lantus (Sanofi): Available — SoloStar pens and vials in production. Intermittent pharmacy-level stockouts in high-demand areas.
• Rezvoglar KwikPen (Eli Lilly): Available — biosimilar interchangeable with Lantus. Good availability.
• Generic Insulin Glargine (Winthrop and others): Available — vials and pens; regional variation in supply.
• Semglee (Biocon/Viatris): Discontinued as of December 31, 2025. Patients must be transitioned.

Why Localized Stockouts Are Occurring

Basaglar's national supply is intact, but clinicians are seeing patients report pharmacy-level unavailability. The primary driver is demand displacement from Semglee's exit. Semglee held substantial market share as the first interchangeable biosimilar to Lantus — its December 2025 discontinuation redirected millions of patients simultaneously to remaining insulin glargine options.

Pharmacies that did not historically stock large quantities of Basaglar are now experiencing demand they weren't positioned to meet, creating gaps between ordering cycles. Insurance formulary transitions are also adding friction — some plans are still mid-update, creating claims rejections or coverage confusion at the point of dispensing.

Tempo Pen Discontinuation: Provider Action Required

Providers should proactively review their panel for patients on Basaglar Tempo Pens and rewrite prescriptions to the Basaglar KwikPen. Key points:

• Tempo Pens are available only through July 27, 2026.
• KwikPen dose is identical to Tempo Pen (100 units/mL, 1:1 conversion).
• The TempoSmart app (which provided connected dosing data) will become non-functional for data recording after July 28, 2026.
• No dose adjustment is needed for the Tempo Pen to KwikPen transition.

Switching Protocols: Dose Conversions at a Glance

For patients who cannot fill Basaglar and require a switch to an alternative, use the following conversion guidance (always with appropriate glucose monitoring):

• Basaglar → Lantus or Rezvoglar: 1:1 unit conversion. Same concentration (U-100), same mechanism. Minimal disruption expected.
• Basaglar → Toujeo (U-300 insulin glargine): Start at 80% of Basaglar unit dose. Different pharmacokinetics; may require titration upward by 10–15% over first weeks. Monitor closely.
• Basaglar → Tresiba (insulin degludec U-100): Start at same unit dose. Tresiba's ultra-long duration (>42 hours) means patients may need dose reduction if hypoglycemia occurs during transition.
• Basaglar → Levemir (insulin detemir): Start at same unit dose once daily; assess need for twice-daily dosing based on FBG patterns. Some patients require split dosing.

Interchangeability and Substitution: What Pharmacists Can and Cannot Do

Basaglar is classified as a follow-on insulin glargine, not an FDA-designated biosimilar or interchangeable product. Pharmacists cannot substitute Basaglar for Lantus or Rezvoglar without a new prescription. When writing the Rx, be explicit about which product you intend — this reduces dispensing confusion during formulary transitions.

Rezvoglar (insulin glargine-aglr) is FDA-designated interchangeable with Lantus — pharmacists may substitute Rezvoglar for Lantus without prescriber intervention. If your patient's plan now covers Rezvoglar as the preferred formulary alternative to their discontinued Semglee, this substitution is pharmacist-authorized.

Patient Assistance and Savings Resources

For patients facing cost barriers on Basaglar, the following programs are currently active:

• Lilly Insulin Value Cash Savings Card: $35/month cap, no insurance required, up to 14 uses/year, valid through December 31, 2026. Available at insulinaffordability.com.
• Lilly Insulin Value Commercial Savings Card: Commercially insured patients pay as little as $35/month (max $3,000/fill, $16,000/year). Available at basaglar.com/savings-resources.
• Lilly Cares Foundation Patient Assistance Program: Free medication for eligible uninsured/underinsured patients. Income thresholds apply (approximately single <$40,000, couple <$60,000). Call 1-800-545-5979.
• Medicare Part D: For patients with covering plans, insulin costs capped at $35/month (2026).

Helping Patients Find Basaglar In Stock

When patients report pharmacy-level unavailability, direct them to medfinder for providers. medfinder calls pharmacies in a patient's area to check which ones can fill their prescription — returning results via text. This reduces the burden on patients of calling pharmacies themselves and helps your practice avoid unnecessary prescription rewrites for supply-related issues that may be temporary and localized.

For a deeper dive into provider-side strategies, see our companion guide: How to help your patients find Basaglar in stock.