Carbonic-Anhydrase Inhibitors, Eyedrops
Type of Drug
Carbonic-Anhydrase Inhibitors,
Eyedrops (kar-BON-ik an-HYE-drase)
Brand Names
Generic Ingredient: Dorzolamide Trusopt
Generic Ingredient: Brinzolamide Azopt
Combination Product
Generic Ingredients: Dorzolamide + Timolol Cosopt
Prescribed For Glaucoma.
General Information
These drugs are similar to acetazolamide, a carbonic-anhydrase inhibitor taken by mouth. Carbonic anhydrase is an enzyme found in many parts of the body, including the eyes. By blocking the effects of this enzyme, dorzolamide and brinzolamide slow the production of fluid inside the eye, reducing pit:ssure. This cffc,, i3 usetul in ir83t
ino, open-angle glaucoma because the disease is characterized by elevated eye pressure. Dorzolamide and brinzolamide are sulfonamides, or sulfa drugs, and although they are administered topically, they affect the body systemically.
Cautions and Warnings
Do not use these drugs if you are allergic or sensitive to any of their ingredients or to other sulfa drugs. Small amounts of these drugs enter the bloodstream. Rarely, people using them experience side effects or allergies associated with sulfa drugs.
These drugs have not been studied in people with very poor kidney or liver function. Since these drugs are eliminated via the kidneys, people with impaired kidney function should use an alternate glaucoma medication.
These drugs have not been studied in people with acute angle-closure glaucoma.
See Timolol, page 1129, for more information on the combination product Cosopt.
Possible Side Effects
Dorzolamide
✓ Most common: eye burning, stinging, or discomfort and a bitter taste in the mouth immediately after administering the eyedrops.
✓ Less common: allergic reactions, conjunctivitis (pinkeye), blurred vision, tearing, dry eye, and increased sensitivity to bright light.
♦ Rare: headache, nausea, weakness, tiredness, rash, and kidney stones. Dorzolamide can cause the same types of side effects as other sulfa drugs, but this is very unlikely. Contact your doctor if you experience any side effects not listed above.
Brinzolamide
♦ Common: blurred vision and a bitter, sour, or unusual taste in the mouth.
♦ Less common: eyelid inflammation; conjunctivitis (pink-
eyeY, nsh; dry eye; sensation of something in the eye;
headache; eye redness, itching, discharge, or pain; and
runny nose.
✓ Rare: allergic reactions, hair loss, chest pain, diarrhea, nausea, sore throat, tearing, itchy rash, double vision, dizziness, Possible Side Effects (continued)
dry mouth, breathing difficulties, upset stomach, tired eyes, kidney pain, cornea problems, and formation of a crust or sticky sensation around the eyelid. Brinzolamide can cause the same types of side effects as other sulfa drugs, but this is very unlikely. Contact your doctor if you experience any side effect not listed above.
Drug Interactions
• If you are using more than 1 eyedrop product, separate doses of these drugs by at least 10 minutes.
Usual Dose
Adult: 1 drop in the affected eye 3 times a day. Overdosage
Accidental ingestion of a bottle of dorzolamide or brinzolamide may affect blood levels of potassium and other electrolytes. The victim should be taken to a hospital emergency room. ALWAYS bring the prescription bottle or container.
Special Information
Call your doctor and stop using your eyedrops if you develop any unusual eye reaction or condition, including swollen eyelids and conjunctivitis (pinkeye).
Vision may be temporarily blurred when using the eyedrops. Use caution when driving or operating machinery.
If you wear soft contact lenses, take them out before using the eyedrops and put them back in 15 minutes after a dose.
To prevent infection, do not allow the eyedropper tip to touch your fingers, eyelids, or any surface. Wait at least 10 minutes before using any other eyedrops.
If you forget to administer a dose, do so as soon as you remember. If it is almost time for your next dose, skip the one you forgot and continue with your regular schedule. Do not take a double dose.
Special Populations
Pregnancy/Breast-feeding: Very high dosages of dorzolamide or brinzolamide caused birth defects in animal studies. While the risks of using these drugs during pregnancy are small in people, pregnant women should use dorzolamide or brinzolamide only after discussing its potential benefits and risks with their doctors.
it is not known if these drugs pass into breast milk. Nursing mothers who must use either drug should use infant formula.
Seniors: Seniors may be more sensitive to side effects.