What Is timolol?

Timolol (also known by brand names Timoptic, Betimol, Istalol, and Blocadren) is a nonselective beta-adrenergic blocker (beta-blocker) that has been used for decades to treat eye and heart conditions. In its ophthalmic form, timolol is one of the most widely prescribed medications for open-angle glaucoma and ocular hypertension, helping to lower intraocular pressure and prevent vision loss. In its oral tablet form, timolol is approved for hypertension (high blood pressure), migraine prophylaxis, and to improve survival after a heart attack. It is also used off-label as a topical treatment for infantile hemangiomas.

How does timolol work?

Timolol works by blocking both beta-1 and beta-2 adrenergic receptors in the body. In the eye, it reduces the production of aqueous humor (the fluid inside the eye) by inhibiting beta-receptors on the ciliary epithelium. This lowers intraocular pressure (IOP), which is the primary risk factor for glaucoma progression. In the cardiovascular system, timolol reduces heart rate, cardiac output, and blood pressure by blocking beta-1 receptors in the heart. For migraine prevention, the exact mechanism is not fully understood but is thought to involve stabilization of vascular tone. Timolol is typically instilled as one drop in the affected eye(s) twice daily (or once daily for the gel-forming solution), with nasolacrimal occlusion recommended to minimize systemic absorption.

What doses are available for timolol?

• Ophthalmic solution: 0.25% and 0.5% (typically 5 mL or 10 mL bottles)
• Ophthalmic gel-forming solution (Timoptic-XE): 0.25% and 0.5% (5 mL)
• Preservative-free ophthalmic solution (Timoptic in Ocudose): 0.25% and 0.5% (single-use containers)
• Oral tablets (Blocadren): 5 mg, 10 mg, and 20 mg

How hard is it to find timolol in stock?

Timolol has a findability score of 55 out of 100, meaning it can be moderately difficult to find depending on the formulation. The standard generic ophthalmic solution (0.25% and 0.5%) is generally available through manufacturers like Apotex. However, the gel-forming solution (generic Timoptic-XE) is currently on back order from Sandoz with no estimated release date. The preservative-free formulation (Timoptic in Ocudose) and the dorzolamide/timolol combination have also experienced supply disruptions due to manufacturing delays. If your pharmacy is out of stock, ask about switching formulations or try Medfinder to locate availability near you.

Who Can Prescribe timolol?

Timolol eye drops are most commonly prescribed by ophthalmologists and optometrists for glaucoma and ocular hypertension. Oral timolol tablets may be prescribed by primary care physicians, cardiologists (for hypertension and post-MI management), and neurologists (for migraine prophylaxis). Timolol is also available through telehealth consultations for prescription renewals, making it accessible for patients with established diagnoses.

Is timolol a controlled substance?

No, timolol is not a controlled substance. It is not classified under any DEA schedule. Timolol is a standard prescription medication with no known potential for abuse or dependence. Refills are straightforward and do not require special prescribing procedures.

Common Side Effects of timolol

• Eye stinging or burning upon instillation (ophthalmic)
• Blurred vision temporarily after using drops
• Eye redness or irritation
• Dry eyes
• Fatigue
• Dizziness
• Headache
• Bradycardia (slow heart rate) — even with eye drops due to systemic absorption
• Cold hands and feet

Serious side effects are rare but can include severe bradycardia, heart failure exacerbation, bronchospasm (which can be fatal in patients with asthma), hypotension, and depression. Timolol eye drops can mask symptoms of low blood sugar in diabetic patients. Do not stop timolol abruptly — talk to your doctor about tapering to avoid rebound effects.

Alternative Medications to timolol

If you're having trouble finding timolol or it's not the right fit, your doctor may consider these alternatives:

• Latanoprost (Xalatan) — A prostaglandin analog and one of the most commonly used first-line treatments for glaucoma. Used once daily at bedtime.
• Betaxolol (Betoptic) — A selective beta-1 blocker eye drop that may be safer for patients with lung disease such as asthma or COPD.
• Dorzolamide (Trusopt) — A carbonic anhydrase inhibitor eye drop that lowers eye pressure through a different mechanism.
• Brimonidine (Alphagan) — An alpha-2 agonist eye drop that both reduces aqueous humor production and increases outflow.

Talk to your eye doctor about which option is best for your situation, especially if timolol is unavailable in your area.

Drug Interactions with timolol

• Calcium channel blockers (verapamil, diltiazem) — Increased risk of dangerously slow heart rate, AV block, and heart failure when used together.
• Other beta-blockers — Additive effects; avoid using oral and ophthalmic beta-blockers simultaneously without medical supervision.
• Clonidine — Risk of severe rebound hypertension if clonidine is discontinued while on timolol.
• Digitalis glycosides (digoxin) — Additive bradycardia risk.
• CYP2D6 inhibitors (quinidine, fluoxetine, paroxetine) — May increase timolol blood levels and side effects.
• Epinephrine — Timolol may reduce the effectiveness of epinephrine during anaphylaxis treatment.
• Insulin and oral hypoglycemics — Timolol can mask warning signs of low blood sugar.
• NSAIDs — May reduce the blood-pressure-lowering effect of oral timolol.

Always inform your doctor and pharmacist about all medications you are taking, including other eye drops.

Final Thoughts on timolol

Timolol remains one of the most affordable and effective treatments for glaucoma and ocular hypertension, with generic ophthalmic solution available for as little as $4 with a coupon. While certain formulations — particularly the gel-forming solution and preservative-free versions — are experiencing supply disruptions in 2025-2026, the standard ophthalmic solution is generally findable. If your pharmacy is out of stock, use Medfinder to check availability at nearby pharmacies, or ask your doctor about switching to an alternative formulation. With insurance, most patients pay $0 to $15 for generic timolol, making it one of the most cost-effective glaucoma medications on the market.