While there is no cure for glaucoma, it can be controlled with proper management.
Elevated intraocular pressure (IOP) can damage the optic nerve, which may lead to vision loss. Treatment for glaucoma focuses on lowering the IOP to a level that is less likely to cause further optic nerve damage. This is known as the “target pressure.” The target pressure differs from individual to individual. Your target pressure may change during your course of treatment.
If you have glaucoma, your ophthalmologist may prescribe a medication to lower your eye pressure. For glaucoma medications to work, you must take them regularly and as prescribed by your doctor.
With each new medication that your ophthalmologist prescribes, make sure you understand the following:
- the name of the medication;
- how to take it;
- how often to take it;
- how to store it;
- if you can take it with your other medications (make sure all of your doctors know about all the different medications you take, including nonprescription medications);
- what the possible side effects may be;
- what you should do if you experience side effects; and
- what you should do if you miss a dose.
There are several different medications available for the treatment of glaucoma including 1) beta-blockers, 2) prostaglandin analogues, 3) Alpha agonists, 4) carbonic anhydrase inhibitors, and 5) combined agents.
Beta-Blockers in the Treatment of Glaucoma
How Do Beta Blockers Work?
Beta-blocker (beta adrenergic antagonist) medications are reliable for lowering intraocular pressure. They work by decreasing the amount of fluid that the eye continually produces, called the aqueous humor. For many years, beta blockers were the mainstay of treatment. Thus, we have a lot of experience with this medication for the treatment of glaucoma.
Types of Beta-Blocker Medications
There are two general classes of beta blockers: nonselective and selective. Nonselective beta blockers have more effects on the body’s beta receptors system-wide and are associated with more side effects. The nonselective beta blockers are also more effective at lowering IOP.
The nonselective beta blockers include
- levobunolol (Betagan, AKBeta);
- timolol (Timoptic); and
- timolol gel (Timoptic XE).
- Generic versions of timolol and timolol gel are now available. Consult with your ophthalmologist to be sure that a generic product is an acceptable alternative for you.
The only available selective beta-blocker medication is
- betaxolol (Betoptic, Betoptic S).
- Betaxolol is the generic form of Betoptic.
While a selective beta-blocker eyedrop has a better safety profile, especially in terms of respiratory symptoms, it still must be used with caution in patients with asthma or emphysema. The eye pressure-lowering effect is slightly less with selective beta blockers. There is only a minimal additive effect in terms of lowering eye pressure in patients already taking oral beta blockers, and there is the risk of further additive side effects. If you are already taking a beta-blocker medication by mouth or if your primary care doctor newly prescribes a beta blocker, please notify your ophthalmologist.
Possible Side Effects of Beta Blockers
All medications, including eyedrops, can have side effects. Some people taking beta-blocker eyedrops may experience
- wheezing or difficulty breathing;
- slow or irregular heart beat or decreased response of heart rate to exercise;
- increased risk for heart failure;
- headache, dizziness or weakness;
- in diabetics, difficulty sensing blood glucose changes; and
- eye irritation or allergy.
Prostaglandin Analogs/Prostamides in the Treatment of Glaucoma
How do prostaglandin analogs or prostamides work?
Prostaglandin analogs and prostamides lower IOP by increasing the outflow of the aqueous humor, the fluid made continuously by the eye. All of these medications are taken once a day, except for Rescula, which is taken twice per day.
What are the prostaglandin analog and prostamide medications?
- latanoprost (Xalatan)
- bimatoprost (Lumigan)
- travoprost (Travatan) Lumigan
Possible side effects of prostaglandin analogs or prostamides
All medications, including eyedrops, can have side effects. Some people taking these eyedrops may experience:
- redness of the eye
- darkening of the iris (the colored part of the eye); this color change occurs slowly and may not be noticeable for months or even years;
- increased growth, thickness, and pigmentation of the eyelashes;
- eye irritation or itching;
- blurred vision;
- darkening of the eyelid skin;
- muscle aches (rare); and
- headaches (rare). Xalatan
Patients with a history of uveitis (inflammation in the eye), ocular herpes infection, or swelling in the retina (called cystoid macular edema) should use this medication with caution. If you have a history of any of these conditions, please discuss it with your doctor.
Alpha-Agonists in the Treatment of Glaucoma
How Do Alpha Agonists Work?
Alpha agonist medications are reliable for lowering the intraocular pressure. They work by decreasing the production of the fluid that the eye continually makes, called the aqueous humor.
What Are the Alpha Agonists?
There are three alpha agonist drugs:
- apraclonidine (Iopidine);
- brimonidine (Alphagan, Alphagan P); and
- dipivefrin (Propine).
A generic version of Alphagan called brimonidine is available.
Possible Side Effects of Alpha Agonists
All medications, including eyedrops, can have side effects. Some people taking alpha agonist eyedrops may experience:
- dry mouth;
- ocular allergy with a red eye or red eyelids (30% of patients);
- tiredness or fatigue;
- low or high blood pressure and possible slowing of heart rate (less than with beta blockers);
- blurred vision;
- sensitivity of the eyes to bright light; and
Carbonic Anhydrase Inhibitors (CAIs) in the Treatment of Glaucoma
How Do CAIs Work?
CAI medications are very reliable at lowering the intraocular pressure. They work by decreasing the production of the fluid that the eye continually makes, called the aqueous humor.
What Are CAI Medications?
- dorzolamide (Trusopt); and
- brinzolamide (Azopt).
- acetazolamide (Diamox, AK-Zol);
- acetazolamide sustained-release (Diamox Sequels); and
- methazolamide (Neptazane, GlaucTabs).
Generic versions of the eyedrop formulations are not yet available.
Possible Side Effects of CAIs
All medications, including eyedrops, can have side effects. Some people taking topical carbonic anhydrase medications (eyedrops) experience:
- blurred vision
- bitter taste in the mouth
- dry eyes
- eye irritation or allergy with a red eye or red eyelids
- headache or dizziness
- upset stomach.
The oral (pill) form of these medications has more side effects, including:
- increased need to urinate;
- tingling sensation in fingers and toes;
- rarely, severe allergic reactions or blood disorders can occur;
- change in taste (especially with carbonated beverages); and
- unusual tiredness or weakness.
These medications are sulfonamides. If you are allergic to sulfa antibiotics, the same types of adverse reactions can occur with carbonic anhydrase inhibitors. Also, rare adverse drug interactions have occurred in patients taking high doses of aspirin and carbonic anhydrase inhibitors.
Combined Agents in the Treatment of Glaucoma
Several eyedrops are available that combine the actions of two drugs from different categories. The reasoning behind the use of combined agents is that it is easier for patients to put just one drop in their eyes instead of two; it may also be healthier for the eye as less preservative is being applied.
What are the combined medications?
- Combigan (Combines a beta-blocker and an alpha-agonist)
- Cosopt (Combines a beta-blocker and a CAI)
- DuoTrav (Combines a prostaglandin analog and a beta-blocker)
- Xalacom (Combines a prostaglandin analog and a beta-blocker) DuoTrav
For glaucoma medications to work, you must take them regularly and continuously as prescribed by your doctor.