Glaucoma Medications and their Side Effects

A variety of options are available to treat glaucoma. These include eye drops, laser procedures, and surgery. All are intended to decrease eye pressure and, thereby, protect the optic nerve.

Currently, in the US, eye drops are often the first choice for treating patients. For many people a combination of medications and laser treatment can safely control eye pressure for years.

Eye drops used in managing glaucoma decrease eye pressure by helping the eye’s fluid to drain better and/or decreasing the amount of fluid made by the eye.

Drugs to treat glaucoma are classified by their active ingredient. These include: prostaglandin analogs, beta blockers, alpha agonists, carbonic anhydrase inhibitors, and rho kinase inhibitors. In addition, combination drugs are available for patients who require more than one type of medication. An older class of medications, the cholinergic agonists (such as pilocarpine) are not commonly used these days due to their side effects.

Types of Glaucoma Eye Drops

Prostaglandin analogs include Xalatan® (latanoprost), Lumigan® (bimatoprost), Travatan Z® (Travoprost), and Zioptan™ (tafluprost), and Vyzulta™ (latanoprostene bunod), and they work by increasing the outflow of fluid from the eye. They have few systemic side effects but are associated with changes to the eye itself, including change in iris color and growth of eyelashes. Depending on the individual, one of these preparations may be more effective and produce fewer side effects. Latanoprost and some formulations of bimatoprost are now available in generic form. Tafluprost is a preservative-free prostaglandin analog.

Beta blockers such as timolol are the second most often used class of medication and work by decreasing production of fluid. They are available in generic form and, therefore, may be less expensive. Timolol is also available in a preservative-free formulation. Systemic side effects of beta blockers can be minimized by closing the eyes following application or using a technique called punctal occlusion that prevents the drug from entering the tear drainage duct and systemic circulation.

Alpha agonists [Alphagan®P (brimonidine), Iopidine®] work to both decrease production of fluid and increase drainage. Alphagan P has a purite preservative that breaks down into natural tear components and may be better tolerated in people who have allergic reactions to preservatives in other eye drops. Alphagan is available in a generic form.

Carbonic anhydrase inhibitors (CAIs) reduce eye pressure by decreasing the production of intraocular fluid. These are available as eye drops [Trusopt® (dorzolamide), Azopt® (brinzolamide)] as well as pills [Diamox (acetazolamide) and Neptazane® (methazolamide)]. Except for brinzolamide, all CAIs are available in generic form.

Rho khinase inhibitors [Rhopressa® (netarsudil)] increase the drainage of intraocular fluid. This new class of glaucoma drug has been available since April 2018.

Combined medications can offer an alternative for patients who need more than one type of medication. In addition to the convenience of using one eyedrop bottle instead of two, there is decreased exposure to preservatives. There may also be a financial advantage, depending on your insurance plan. Cosopt® is a combination of a beta blocker (timolol) and a carbonic anhydrase inhibitor (dorzolamide) and is available in generic form and also as a preservative-free formulation (Cosopt® PF). Combigan® combines an alpha agonist (brimonidine) with a beta blocker (timolol). Simbrinza® is a beta blocker-free combination medication consisting of brinzolamide and brimonidine.

Treatment Concerns

Of course, no eye drop medication can be effective if it is not taken as prescribed. There are a number of reasons why people being treated for glaucoma may not take their medications.

One reason is that they simply forget! Remembering to take a daily medication is one of the challenges in the treatment of any chronic condition, and glaucoma is no exception. Some ways to help remember include tying a regular daily activity (such as brushing one’s teeth) to taking one’s medication, or setting timed reminders such as an alarm clock or cell phone.

A second factor in not taking medication as prescribed is economics. Glaucoma drugs can be expensive. Also, some medications may be covered by your insurance while others are not. Your eye doctor will work with you to recommend the best choice for you.

Another factor that influences the use of eyedrops is side effects. Besides adverse reactions specific to the active ingredient, ocular surface irritation (conjuctival and corneal) can occur with any type of eye drop. This irritation can be either new in a patient who never had symptoms before or can manifest as worsening of pre-existing ocular surface disease (such as dry eye, meibomitis, etc.). Preservative-free medications (Zioptan, Cosopt PF, Timoptic in Ocudose) or those without the preservative BAK (Travatan Z, Alphagan P) are often useful in this situation.

Laser Treatment

For patients who cannot tolerate medications or for whom medication alone has not been adequate, laser treatment continues to be an excellent alternative. It should be noted that laser may also be used as primary treatment. The advantage of this approach is that if adequate pressure lowering is achieved with laser treatment alone, the need for taking a daily medication may be delayed, along with the associated side effects.

The effect of laser treatment is typically not permanent, and many patients will eventually require medications. The most common laser treatments for glaucoma are selective laser trabeculoplasty (SLT) and argon laser trabeculoplasty (ALT).

Side Effects of Glaucoma Medications

Following are some of the potential side effects of glaucoma medications.

• Prostaglandin Analogs: eye color change, darkening of eyelid skin, eyelash growth, droopy eyelids, sunken eyes, stinging, eye redness, and itching

• Beta Blockers: low blood pressure, reduced pulse rate, fatigue, shortness of breath; rarely: reduced libido, depression.

• Alpha Agonists: burning or stinging, fatigue, headache, drowsiness, dry mouth and nose, relatively higher likelihood of allergic reaction.

• Carbonic Anhydrase Inhibitors: in eye drop form: stinging, burning, eye discomfort; in pill form: tingling hands and feet, fatigue, stomach upset, memory problems, frequent urination.
• Rho Kinase Inhibitors: eye redness, corneal deposits, stinging, and small bleeds on the white of the eye.

Side effects of combined medications may include any of the side effects of the drug types they contain.

For more information, please see our Glaucoma Medication Guide.

Article by Sunita Radhakrishnan, MD and Andrew G. Iwach, MD.
Posted on September 10, 2016. Last reviewed on March 9, 2022.