Examples
| Generic Name | Brand Name |
|---|
| apraclonidine hydrochloride | Iopidine |
| brimonidine tartrate | Alphagan |
| dipivefrin hydrochloride | Propine |
| epinephrine hydrochloride | Epifrin |
These medications are given in eyedrop form. The most commonly used
adrenergic agonist (brimonidine tartrate) eyedrops have a purple bottle cap.
If you need to use more than one type of eyedrop, you may need to
take each medication 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 medications may be used along with other medications to treat
glaucoma.
Apraclonidine and brimonidine are used to treat high pressure in
the eyes in people with
open-angle glaucoma. They are also used to prevent
high pressure in an eye after laser treatment for glaucoma. For everyday use,
brimonidine (Alphagan) is replacing apraclonidine (Iopidine) because it is less
likely to cause an allergic reaction. Some pharmacies no longer carry
apraclonidine eyedrops.
Dipivefrin is converted to epinephrine in the body. Because newer
adrenergic agonists are more effective and have fewer side effects, dipivefrin
is used only rarely.
Epinephrine is rarely used since apraclonidine and brimonidine are
just as effective with fewer side effects.
How Well It Works
These medications 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 medications 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 medication.
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 medication to keep the red out of their eyes.
Apraclonidine and, less
commonly, brimonidine may cause allergy problems in some people when used over
a long period of time.
These medications 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.
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to help you understand this medication.