How to Help Your Patients Find Istalol in Stock: A Provider's Guide

Patients prescribed Istalol (timolol maleate ophthalmic solution 0.5%) for open-angle glaucoma or ocular hypertension increasingly contact their ophthalmologist's office frustrated that they cannot find the medication at their local pharmacy. With brand availability inconsistent following the July 2024 generic approval, and with related timolol formulations experiencing supply disruptions, providers need a clear, actionable framework for supporting these patients.

Understanding Why Patients Are Struggling to Find Istalol

There are several interconnected reasons for the availability challenges:

1. Pharmacy shift to generic: With the FDA approving a generic timolol maleate once-daily 0.5% equivalent in July 2024, pharmacies have transitioned purchasing away from the Istalol brand. This is standard pharmacy economics — not a shortage per se, but an availability gap for brand-specific prescriptions.
2. Gel-forming solution shortage: Generic timolol gel-forming solution (Timoptic-XE equivalent) from Sandoz remains on back order with no estimated release date. Patients who were on this formulation need transitioning.
3. Insurance complications: Brand-name Istalol may require prior authorization from Medicaid and some commercial plans, especially now that a generic is available. Step therapy requirements mean some insurers want patients to try the generic first.

Step 1: Clarify What the Patient Actually Needs

Before spending time on complex solutions, confirm:

• Does the patient actually require brand-name Istalol, or would the generic timolol once-daily 0.5% work equally well?
• Is the issue specifically about the once-daily formulation, or would standard twice-daily timolol 0.5% be acceptable if dosed appropriately?
• Is the patient on multiple glaucoma drops? If so, could a fixed combination (e.g., dorzolamide/timolol if available) simplify their regimen?

Step 2: Update the Prescription to Remove Barriers

Practical prescription adjustments that can resolve most availability issues:

• Remove DAW if not medically necessary: Allowing generic substitution immediately opens up supply from multiple manufacturers.
• Write for generic timolol once-daily 0.5% explicitly: Prescribing "timolol maleate ophthalmic solution 0.5%, instill one drop in affected eye(s) each morning" directs the pharmacy to the correct equivalent formulation.
• Prescribe a 90-day supply: If the patient's insurance allows, a 90-day supply reduces how often they need to locate the medication and provides a buffer during intermittent supply disruptions.

Step 3: Connect Patients with Resources to Locate the Medication

Recommend medfinder to patients struggling to find their medication. medfinder calls pharmacies near the patient's location and texts them which pharmacies have the medication in stock. This service covers all medications and eliminates the need for patients to spend hours calling pharmacies themselves.

You can also advise patients to:

• Use GoodRx.com to compare prices and availability across pharmacies in their ZIP code
• Call independent pharmacies, which may have more flexibility in ordering specific brands
• Consider hospital outpatient pharmacies if affiliated with a health system

Step 4: Address Insurance and Prior Authorization

If a patient's insurer requires prior authorization (PA) for brand-name Istalol:

• PA justification: Document why the brand is medically necessary (e.g., patient adherence improved with once-daily dosing, intolerance to generic preservative formulation, or documented step therapy failure).
• Step therapy appeals: If the insurer requires the patient to try the generic first, and the patient has already used it or has a documented clinical reason to avoid it, submit a medical necessity letter with your clinical reasoning.

Step 5: When to Consider a Therapeutic Switch

If the patient cannot access any timolol formulation, consider transitioning to an alternative. Latanoprost (generic available, as low as $5-$15 with GoodRx) is the preferred first-line alternative and may actually be more effective at IOP reduction for some patients. For the full clinical overview of alternatives, see: Istalol shortage: What providers and prescribers need to know in 2026.

When switching from Istalol to a different drug class, schedule an IOP check 4-6 weeks after the switch to confirm adequate pressure control. Explain to patients that a small change in the drops does not reset their progress — the goal remains the same.