Dorzolamide belongs to the family of medications called carbonic anhydrase inhibitors. Dorzolamide is used to reduce the pressure inside the eye for people with open-angle glaucoma or ocular hypertension (increased pressure in the eye).

Fluid is constantly being formed and drained out of the eye. When this fluid does not drain out of the eye properly or too much fluid is produced, pressure inside the eye increases. Dorzolamide works by reducing the amount of fluid produced by the eye.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are being given this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.

The recommended adult dose of dorzolamide eye drops is one drop in the affected eye(s) 3 times daily.

If dorzolamide is used at the same time as beta-blocker eye drops for treating increased pressure in the eye, the recommended dose is one drop in the affected eye(s) twice daily.

To use the eye drops:

• Wash your hands before using the eye drops.
• Remove the cap and place it in a clean location. To avoid possible contamination, keep the tip of the container away from contact with any surface.
• Tilt your head back and look towards the ceiling.
• With your index finger, and gently pull the lower eyelid down and away from the eye to form a pouch.
• Apply one drop into the pouch by following the instructions on the eye drop container. Do not allow the tip of the container to touch the eye or areas around the eye.
• Gently apply pressure to the inner corner of the eye (at the bridge of the nose) for about 30 seconds (this is called nasolacrimal occlusion). This prevents the medication from dripping down through the tear duct and entering the bloodstream, which could cause you to experience some side effects.
• Repeat with the other eye, if prescribed by your physician.
• Wash your hands again to remove any medication.

If you are using the preservative-free eye drops:

• Wash your hands before using the eye drops.
• Break off one pipette from the strip of 5 contained in each foil pouch. Twist the top of the pipette to open the top of the container.
• Tilt your head back and look towards the ceiling.
• With your index finger, and gently pull the lower eyelid down and away from the eye to form a pouch.
• Apply one drop into the pouch but do not allow the tip of the container to touch the eye or areas around the eye.
• Gently apply pressure to the inner corner of the eye (at the bridge of the nose) for about 30 seconds (this is called nasolacrimal occlusion). This prevents the medication from dripping down through the tear duct and entering the bloodstream, which could cause you to experience some side effects.
• Repeat with the other eye, if prescribed by your physician.
• Wash your hands again to remove any medication.
• Safely discard any solution remaining in the pipette and return the remaining pipettes to the foil pouch.
• Once a foil pouch has been opened, the pipettes must be used within 15 days. Discard any unused pipettes after 15 days.

Do not allow the bottle's dropper tip to touch the eye or other surrounding structures. This can contaminate the tip with common bacteria known to cause eye infections. Serious damage to the eye may result if you use eye drop solutions that have become contaminated.

Dorzolamide eye drops should be used at least 10 minutes before or after other eye drops that are being used.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are using the medication without consulting your doctor.

It is important to use this medication exactly as prescribed by your doctor. If you miss a dose, instill it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not instill a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light, and keep it out of the reach of children. Store the preservative-free form in its foil pouch.

2%
Each 1 mL of sterile, clear, colourless-to-nearly-colourless ophthalmic solution contains dorzolamide 20 mg (2%). Nonmedicinal ingredients: benzalkonium chloride 0.0075% (as preservative), hydroxyethyl cellulose, mannitol, sodium citrate dihydrate, sodium hydroxide (to adjust pH), water for injection.

Dorzolamide should not be used by anyone who:

• is allergic to dorzolamide or to any of the ingredients of the medication
• is taking carbonic anhydrase inhibitors (e.g., acetazolamide) by mouth
• has severe kidney impairment

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• bitter taste after putting in your eye drops
• burning, stinging, or discomfort when eye drops are used
• crusting on eyelid or corner of the eye
• dry mouth
• eye discharge
• headache
• nausea
• nosebleed
• redness of the eyes
• tearing (eyes produce excess teardrops)
• throat irritation
• unusual tiredness or weakness

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• blurred vision
• dizziness
• eye pain
• feeling of something in the eye
• itching, redness, swelling, or other signs of eye or eyelid irritation
• nose bleeds
• sensitivity of the eye to sunlight
• skin rash
• symptoms of kidney stones (e.g., blood in urine; nausea or vomiting; pain in side, back, or abdomen)
• tingling in the extremities (hands or feet)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• symptoms of an allergic reaction (e.g., difficulty breathing, hives, itchy and raised skin rash, or swelling of the mouth and throat)
• symptoms of severe skin reaction (e.g., skin blisters, severe red or purple rash or itching, skin lesions and sores, fever, or sore throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergy: Dorzolamide belongs to the family of medications known as sulfonamides or "sulfas." The same type of allergic reaction can occur with this medication as with other sulfonamides. People with allergies to sulfonamides should discuss with their doctor the risks and benefits of using this medication. Stop using this medication and contact your doctor if you experience symptoms of an allergic reaction (e.g., difficulty breathing, hives, skin rash, swelling of the mouth and throat).

Blurred vision: Side effects such as blurred vision may affect the ability to drive and operate machinery. Do not drive, operate machinery, or engage in any potentially hazardous activities until you determine how this medication affects you.

Choroidal detachment: Anyone with chronic or recurrent choroidal detachment should talk to their doctor about further use of the eye drop.

Contact lenses: If you wear contact lenses, remove the lenses before using the eye drops and wait at least 15 minutes before re-inserting them.

Eye surgery, eye (corneal) defect, infections, trauma: Anyone using this medication who has had eye surgery, pre-existing long-term eye (corneal) defect, trauma to the eye, or who has symptoms of an eye infection (e.g., eye redness, itchiness, discharge, crusts on the eyelids, or the feeling of something in the eye) should contact their doctor concerning further use of the eye drop.

General: As with other topically applied eye drops, this medication may be absorbed into the bloodstream. The same side effects reported with oral medications such as carbonic anhydrase inhibitors (e.g., acetazolamide, methazolamide) or sulfonamides (e.g., sulfamethoxazole) may occur with the eye drops. These side effects may include, but are not limited to, rash and nausea. Refer to the "What side effects are possible with this medication?" section for more information.

Kidney disease: If you have kidney disease, discuss with your doctor how this medication may affect their medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. People with severe kidney impairment should not use dorzolamide.

Liver disease: If you have liver disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if dorzolamide passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children.

There may be an interaction between dorzolamide and any of the following:

• amantadine
• other carbonic anhydrase inhibitors (e.g., acetazolamide, brinzolamide, topiramate)
• ephedrine
• pseudoephedrine

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.