What Is Cosopt?

Cosopt is a prescription combination eye drop used to treat elevated intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension. It combines two active ingredients — Dorzolamide (a carbonic anhydrase inhibitor) and Timolol (a beta-blocker) — into a single convenient drop. Cosopt is typically prescribed for patients who need more IOP reduction than a single medication can provide, or who haven't responded adequately to beta-blockers alone. It is also sometimes used off-label for angle-closure glaucoma and secondary glaucoma.

How does Cosopt work?

Cosopt lowers intraocular pressure through two complementary mechanisms:

• Dorzolamide inhibits the enzyme carbonic anhydrase in the ciliary processes of the eye, which reduces the formation of bicarbonate ions and slows aqueous humor secretion.
• Timolol is a non-selective beta-adrenergic antagonist that reduces aqueous humor production by blocking beta receptors in the ciliary body.

By targeting two different pathways simultaneously, Cosopt provides greater IOP reduction than either component alone. This dual mechanism helps protect the optic nerve from damage caused by elevated eye pressure.

What doses are available for Cosopt?

• Cosopt Ophthalmic Solution — Dorzolamide 2% / Timolol 0.5% in a 10 mL bottle (contains preservative benzalkonium chloride)
• Cosopt PF (Preservative-Free) — Dorzolamide 2% / Timolol 0.5% in single-use vials (for patients sensitive to preservatives)

The typical dose is one drop in the affected eye(s) twice daily. Both formulations contain the same active ingredient concentrations.

How hard is it to find Cosopt in stock?

Cosopt (Dorzolamide/Timolol) scores a 75 out of 100 on our findability scale, meaning it is generally available at most pharmacies with only minor gaps. The generic version is manufactured by several companies and is widely stocked. However, Cosopt has experienced periodic shortages historically — most notably in 2017–2018 when manufacturing delays affected multiple generic producers. The 2023 bankruptcy of Akorn, a major generic manufacturer, reduced the number of supply sources. As of early 2026, Cosopt is not on the FDA Drug Shortage List, but sporadic availability issues have been reported by patients. If your local pharmacy is out of stock, Medfinder can help you locate pharmacies that have it available near you.

Who Can Prescribe Cosopt?

Cosopt is most commonly prescribed by:

• Ophthalmologists — eye surgeons who specialize in diagnosing and treating glaucoma and other eye conditions
• Optometrists — eye care providers licensed to prescribe medications for glaucoma management in most states
• Primary care physicians — may occasionally prescribe Cosopt, though they typically refer patients to eye specialists for glaucoma treatment

Telehealth prescribing is generally not available for Cosopt since glaucoma diagnosis requires in-person eye exams with specialized equipment (tonometry, visual field testing, and optic nerve imaging).

Is Cosopt a controlled substance?

No, Cosopt is not a controlled substance. It has no DEA scheduling and no potential for abuse or dependence. You can transfer prescriptions between pharmacies without restrictions and obtain refills through standard prescription processes. This makes it easier to shop around for the best price or find it in stock at a different pharmacy if your usual one is out.

Common Side Effects of Cosopt

• Bitter or unusual taste in the mouth (most common)
• Burning or stinging sensation in the eye after instillation
• Blurred vision (usually temporary)
• Tearing or watery eyes
• Eye redness
• Eye itching
• Eyelid crusting
• Sensitivity to light

Serious side effects are less common but may include bronchospasm (especially in patients with asthma or COPD), slow heart rate, severe allergic reactions, corneal erosion, and mood changes. Contact your doctor immediately if you experience difficulty breathing, chest pain, or swelling of the face or throat.

Alternative Medications to Cosopt

If you cannot find Cosopt or it's not the right fit, your doctor may consider these alternatives:

• Combigan (Brimonidine/Timolol) — another combination eye drop that pairs a beta-blocker with an alpha agonist instead of a carbonic anhydrase inhibitor
• Simbrinza (Brinzolamide/Brimonidine) — a beta-blocker-free combination for patients who cannot tolerate Timolol
• Latanoprost (Xalatan) — a prostaglandin analog and common first-line monotherapy for glaucoma
• Rocklatan (Netarsudil/Latanoprost) — a newer combination drop that targets different IOP-lowering pathways

Always consult your ophthalmologist before switching medications, as each option has different side effect profiles and efficacy considerations.

Drug Interactions with Cosopt

Cosopt can interact with several medications due to its beta-blocker and carbonic anhydrase inhibitor components:

• Oral beta-blockers (e.g., Metoprolol, Atenolol) — additive beta-blocking effects increasing risk of hypotension and bradycardia
• Calcium channel blockers (e.g., Verapamil, Diltiazem) — additive cardiac effects and risk of AV conduction problems
• Oral carbonic anhydrase inhibitors (e.g., Acetazolamide) — additive effects; combination not recommended
• Catecholamine-depleting drugs (e.g., Reserpine) — additive hypotension and bradycardia
• CYP2D6 inhibitors (e.g., Quinidine, SSRIs like Fluoxetine) — may increase systemic Timolol levels
• Clonidine — risk of rebound hypertension if Clonidine is discontinued
• Injectable Epinephrine — may be less effective for anaphylaxis treatment while on beta-blockers

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

Final Thoughts on Cosopt

Cosopt remains a valuable and widely used treatment for glaucoma and ocular hypertension in 2026. The generic version (Dorzolamide/Timolol) is affordable — often under $25 with discount coupons — and is stocked at most major pharmacies. While periodic supply disruptions can occur, the medication is not currently in shortage. If you're having trouble finding Cosopt at your local pharmacy, try Medfinder to quickly check real-time availability at pharmacies near you. For patients on a tight budget, manufacturer patient assistance programs and discount cards from GoodRx or SingleCare can significantly reduce out-of-pocket costs.