What Is Istalol? Uses, Dosage, and What You Need to Know in 2026

Istalol is a prescription eye drop used to lower pressure inside the eye in people with open-angle glaucoma or ocular hypertension. Here's everything patients need to know about this medication in 2026 — from how it works and how to use it correctly to its costs and availability.

What Is Istalol?

Istalol is the brand name for timolol maleate ophthalmic solution 0.5%, manufactured by Bausch + Lomb. Timolol maleate belongs to the drug class known as non-selective beta-adrenergic blockers, or beta-blockers. The drug was first approved by the FDA for ophthalmic use in 1978 (under other brand names), and Istalol's specific once-daily formulation received FDA approval on June 4, 2004.

A generic equivalent (timolol maleate ophthalmic solution 0.5%, once-daily) was approved by the FDA in July 2024 and is manufactured by Somerset Theraps LLC. It is therapeutically equivalent to the Istalol brand.

What Is Istalol Used For?

Istalol is FDA-approved for the treatment of elevated intraocular pressure (IOP) in patients with:

• Open-angle glaucoma: The most common form of glaucoma, where the optic nerve is gradually damaged due to elevated IOP. It often has no symptoms until significant vision loss has occurred.
• Ocular hypertension: Elevated IOP without yet causing optic nerve damage or vision loss. Treatment can help prevent progression to glaucoma.

Istalol should NOT be used alone to treat angle-closure glaucoma, which requires immediate treatment to reopen the eye's drainage angle. In a double-masked clinical study of 332 patients, Istalol 0.5% once daily (morning) reduced mean IOP from 25 mm Hg at baseline to approximately 18 mm Hg at peak — equivalent to standard timolol 0.5% twice daily.

How Do You Use Istalol Correctly?

Proper technique is essential for Istalol to work effectively and to minimize side effects:

1. Wash your hands thoroughly before touching the bottle or your eye
2. Tilt your head back and pull down your lower eyelid to create a small pocket
3. Hold the dropper above your eye without touching the dropper tip to your eye, eyelid, or any other surface
4. Instill ONE drop in the affected eye(s) in the morning
5. After instillation, gently press your finger on the inner corner of your eye (the tear duct area) for 1-2 minutes — this nasolacrimal occlusion reduces systemic absorption
6. If using other eye drops, wait at least 5 minutes between different drops
7. Replace the bottle cap immediately after use to avoid contamination

What Is the Standard Dose?

The standard dose of Istalol is:

• One drop of Istalol 0.5% in the affected eye(s)
• Once daily, administered in the morning (AM)

This is what makes Istalol unique among timolol formulations — standard timolol solutions require twice-daily dosing to achieve the same IOP control. The once-daily schedule can simplify your routine and improve adherence.

Who Should NOT Use Istalol?

Istalol is contraindicated in patients with:

• Bronchial asthma or history of asthma (can cause fatal bronchospasm)
• Severe chronic obstructive pulmonary disease (COPD)
• Sinus bradycardia (slow heart rate)
• Second or third degree atrioventricular (AV) heart block
• Overt cardiac failure or cardiogenic shock
• Known allergy or hypersensitivity to any component of Istalol

Istalol Cost and Availability in 2026

Brand-name Istalol has an average retail price of approximately $482.74 for a 5 mL bottle without insurance — a significant cost for a medication that's needed monthly. However, patients have several options to reduce this cost:

• Generic timolol maleate 0.5%: As low as $6.99 with a GoodRx coupon — a 98%+ reduction
• Bausch + Lomb Patient Assistance Program: Can provide Istalol at no cost for eligible patients (call 1-855-770-0424)
• Insurance: Commercial and Medicaid plans most commonly cover Istalol; generic timolol is typically Tier 1 on most plans

If you're having trouble locating Istalol at a pharmacy, medfinder can help locate it near you. To understand how Istalol reduces eye pressure at a biological level, read How does Istalol work? Mechanism of action explained in plain English.