What is the most common drug for glaucoma?

October 9, 2025 •

4 min read

According to the Centers for Disease Control and Prevention, more than 3 million Americans are affected by glaucoma, and the most common drug class used as first-line treatment is prostaglandin analogs. These medications are known for their effectiveness and convenient once-daily dosing.

Quick Summary

Prostaglandin analogs represent the most common class of medication used to treat glaucoma. This article details the primary drug, latanoprost, its mechanism, and how it compares to other glaucoma medications to help control intraocular pressure and prevent vision loss.

Key Points

Prostaglandin Analogs: This class of eye drops, which includes latanoprost, bimatoprost, and travoprost, is the most common first-line treatment for glaucoma due to high efficacy and convenient once-daily dosing.
IOP Reduction Mechanism: Prostaglandin analogs lower intraocular pressure by increasing the natural outflow of fluid from the eye through the uveoscleral pathway.
Variety of Medications: Other important drug classes used for glaucoma include beta-blockers, alpha-agonists, carbonic anhydrase inhibitors, and rho kinase inhibitors, each with a different mechanism of action.
Combination Therapy: Fixed-dose combination eye drops combine two different medications to improve efficacy and simplify the dosing schedule for patients who need more than one treatment.
Adherence is Crucial: Consistent daily use of glaucoma eye drops is critical for preventing vision loss, as non-adherence can lead to continued optic nerve damage.
Side Effects: While PGAs are generally well-tolerated, side effects like eye redness, eyelash growth, and changes in iris pigmentation can occur. Other drug classes have distinct side effect profiles.

The most common treatment: Prostaglandin analogs

Glaucoma is a group of progressive eye diseases characterized by damage to the optic nerve, often caused by abnormally high pressure inside the eye, known as intraocular pressure (IOP). Untreated, this can lead to vision loss and irreversible blindness. To manage this, ophthalmologists most frequently prescribe topical eye drops from a class of medications called prostaglandin analogs (PGAs). PGAs are highly effective and are often the first choice for treatment due to their powerful IOP-lowering effect and the convenience of once-daily dosing.

These drugs work by increasing the outflow of the aqueous humor—the fluid produced in the eye—through the uveoscleral pathway, which acts as a secondary drainage route. Common examples of prostaglandin analog eye drops include:

Latanoprost (brand names Xalatan, Xelpros, Iyuzeh)
Bimatoprost (brand name Lumigan)
Travoprost (brand name Travatan Z)
Tafluprost (brand name Zioptan), which is available in a preservative-free formulation

While generally well-tolerated, side effects can include eye redness, eyelash growth, and a permanent darkening of the iris, particularly in people with green-brown eyes.

Other classes of glaucoma medication

If prostaglandin analogs do not lower IOP sufficiently or are not well-tolerated, or if the case is advanced, an ophthalmologist may prescribe other types of eye drops or oral medication. Each class works through a different mechanism to either decrease fluid production or increase fluid outflow.

Beta-blockers: These were once the standard first-line treatment before PGAs became available. They reduce IOP by decreasing the production of aqueous humor in the eye's ciliary body. Examples include timolol (Timoptic) and betaxolol (Betoptic). Side effects can include a slowed heart rate and reduced blood pressure, which makes them unsuitable for some patients with certain heart or lung conditions.
Alpha-adrenergic agonists: These medications have a dual effect, working to both decrease fluid production and increase fluid drainage. A commonly prescribed example is brimonidine (Alphagan P). Possible side effects include eye redness, itching, and dry mouth.
Carbonic anhydrase inhibitors (CAIs): Available in both eye drop and oral forms, CAIs reduce IOP by decreasing the production of intraocular fluid. Examples of eye drops include dorzolamide (Trusopt) and brinzolamide (Azopt). Oral forms like acetazolamide (Diamox) are reserved for more severe cases due to a higher risk of systemic side effects.
Rho kinase inhibitors: This newer class of medication improves fluid drainage through the trabecular meshwork. The only drug in this class is netarsudil (Rhopressa). Side effects can include eye redness and corneal deposits.
Miotic or cholinergic agents: These older medications constrict the pupil to increase fluid outflow but are less commonly used now due to their side effect profile, which can include headaches and reduced vision in dim light. A prominent example is pilocarpine.

Combination medications for optimized treatment

For patients who require more than one type of medication to control their IOP, ophthalmologists can prescribe combination eye drops that contain two different classes of drugs in a single bottle. This reduces the number of drops a patient needs to instill daily, which can significantly improve adherence. Examples include:

Cosopt (dorzolamide and timolol)
Combigan (brimonidine and timolol)
Rocklatan (netarsudil and latanoprost)

Comparison of Glaucoma Medication Classes


Drug Class	Mechanism of Action	Dosing Frequency	Common Examples	Potential Side Effects
Prostaglandin Analogs	Increases uveoscleral outflow	Once daily	Latanoprost (Xalatan), Bimatoprost (Lumigan)	Eye redness, eyelash growth, iris darkening
Beta-Blockers	Decreases aqueous humor production	Once or twice daily	Timolol (Timoptic)	Slowed heart rate, reduced blood pressure, fatigue
Alpha-Adrenergic Agonists	Decreases fluid production and increases outflow	Two to three times daily	Brimonidine (Alphagan P)	Eye redness, dry mouth, irregular heart rate
Carbonic Anhydrase Inhibitors (CAIs)	Reduces aqueous humor production	Two to three times daily (drops)	Dorzolamide (Trusopt), Brinzolamide (Azopt)	Stinging, metallic taste, tingling in extremities (oral)
Rho Kinase Inhibitors	Increases trabecular meshwork outflow	Once daily	Netarsudil (Rhopressa)	Eye redness, corneal deposits

The crucial role of adherence

For glaucoma medication to be effective, it must be used exactly as prescribed by an eye doctor. However, because glaucoma often presents without symptoms, especially in the early stages, patients may become complacent about their daily eye drops. Research has found that adherence is a major hurdle in glaucoma management, with a significant percentage of patients not taking their medication correctly or consistently. Poor adherence can lead to uncontrolled IOP, continued optic nerve damage, and progressive vision loss. Ophthalmologists focus on finding the most effective regimen with the fewest drops and side effects possible to improve adherence. It is vital for patients to communicate any issues with their doctor, whether they are experiencing side effects or simply have trouble remembering their dose.

Conclusion

While a cure for glaucoma is not yet available, effective treatments exist to manage the condition and prevent further vision loss. Prostaglandin analogs, with their high efficacy and convenient once-daily regimen, are the most common first-line medication. However, a wide range of other drug classes and combination drops are available, each with a unique mechanism of action, to tailor treatment to a patient's specific needs. Consistent medication adherence is the cornerstone of successful glaucoma management, and patients must work closely with their ophthalmologist to find and stick with the most suitable treatment plan.

For more in-depth information on glaucoma treatments and research, the Glaucoma Research Foundation is an excellent resource with numerous articles and updates.

Frequently Asked Questions

Prostaglandin analogs (PGAs) are typically the first-line drug class prescribed for treating glaucoma due to their strong intraocular pressure-lowering effect and once-daily application.

Latanoprost may cause a permanent increase in brown pigmentation in the iris, but this side effect is most frequently seen in people who already have some brown eye coloring and is not a universal outcome.

Yes, beta-blockers like timolol are still important and commonly used glaucoma medications. However, they are often a second-line option or combined with other drugs, and they can have systemic side effects that make them unsuitable for some patients.

Common side effects of prostaglandin analogs include mild eye redness, stinging, and itching. More distinctive side effects can include increased eyelash growth and a darkening of the iris.

Forgetting doses can reduce the effectiveness of your treatment and increase the risk of glaucoma progression. It is crucial to use your medication as prescribed daily, and if you miss a dose, you should continue with your next dose at the regular time rather than doubling up.

Yes, if a single eye drop is not enough to control your intraocular pressure, your doctor may prescribe a combination eye drop that contains two different medications. This helps simplify the dosing regimen and can improve adherence.

No, glaucoma eye drops do not cure the disease. They manage it by lowering eye pressure to prevent further damage to the optic nerve. Lifelong treatment is required to prevent progressive vision loss.