Adrenergic Agonists for Glaucoma

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Adrenergic Agonists for Glaucoma


Generic NameBrand Name
brimonidine and timolol Combigan

These medicines are given in eyedrop form. A commonly used adrenergic agonist (brimonidine tartrate) eyedrop has a purple bottle cap. If you need to use more than one type of eyedrop, you may need to take each medicine in a certain order. You can use the colour of the bottle cap to help you remember when to use each type of eyedrop.

If you are using more than one type of eyedrop, wait 5 minutes between the different eyedrop medicines.

How It Works

Most adrenergic agonists reduce the pressure in the eyes by reducing how much fluid (aqueous humour) the eyes produce. They also increase the amount of fluid that drains out of the eyes.

Why It Is Used

These medicines may be used along with other medicines to treat glaucoma.

Brimonidine is used to treat high pressure in the eyes in people with open-angle glaucoma. It is also used to prevent high pressure in an eye after laser treatment for glaucoma.

Epinephrine is rarely used since brimonidine is just as effective with fewer side effects.

How Well It Works

These medicines reduce the pressure in the eyes. Reducing the pressure in the eyes reduces the chances of damage to the optic nerve, preventing further vision loss.

Side Effects

Side effects of adrenergic agonists include:

  • Redness and stinging in the eyes.
  • Allergic reaction in the eyes (itching).
  • Dry mouth (very common with the newer medicines but usually improves over time).
  • Drowsiness, nervousness, and headaches.
  • Fast or irregular heartbeat.
  • Increased blood pressure.

Adrenergic agonists (especially epinephrine) may widen (dilate) the pupil. This may trigger closed-angle glaucoma in people who have narrow drainage angles.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Brimonidine should not be used if a person is taking a monoamine oxidase inhibitor (MAOI), used to treat depression. People who are taking tricyclic antidepressants and those with severe heart, liver, or kidney disease may not be able to take this medicine.

Epinephrine drops tighten (constrict) the blood vessels on the eye's surface, taking the red out of the white part of the eye. After 2 to 3 hours, the vessels open (dilate) and the eye becomes red again. People may be tempted to overuse this medicine to keep the red out of their eyes.

Brimonidine may cause allergy problems in some people when used over a long period of time.

These medicines need to be used with caution in older adults and people who have high blood pressure, diabetes, an overactive thyroid gland (hyperthyroidism), or heart disease.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.


By Healthwise Staff
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Primary Medical Reviewer Anne C. Poinier, MD - Internal Medicine
Specialist Medical Reviewer Christopher J. Rudnisky, MD, MPH, FRCSC - Ophthalmology
Last Revised August 2, 2010

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.