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Dorzolamide eye drops for glaucoma

Eydelto, Trusopt, Vizidor

Dorzolamide eye drops are used to control increased pressure within your eye (glaucoma).

Remember to use the drops regularly - try not to miss any doses.

If you normally wear soft contact lenses, please make sure your doctor knows about this.

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About dorzolamide eye drops

Type of medicine

A carbonic anhydrase inhibitor

Used for

Raised eye pressure, such as in glaucoma

Also called

Trusopt®; Dimaz®; Eydelto®; Vizidor®; Combination brands: Codimaz®; Cosopt®; Eylamdo®; Glaucopt®; Vizidor Duo® (dorzolamide with timolol)

Available as

Eye drops and single-dose units

An increase in pressure within your eye can lead to damage to the optic nerve at the back of your eye. When this occurs it is called glaucoma. Glaucoma can lead to a loss of vision if it is not treated. If you have an increased pressure within your eye but without any damage to the optic nerve, this is called ocular hypertension. People with ocular hypertension have an increased risk of later developing glaucoma. Treatment with dorzolamide eye drops helps to reduce eye pressure in people with ocular hypertension, and to prevent further eye damage in people with glaucoma.

Dorzolamide works by blocking the action of an enzyme called carbonic anhydrase. Blocking this enzyme reduces the amount of fluid that you make in the front part of your eye (called aqueous humour), and this helps to lower the pressure within your eye.

Sometimes, more than one type of eye drop is needed to keep the pressure in the eye low. If this is the case for you, you may be asked to use two different eye drops, or you may be given drops which combine more than one type. Dorzolamide is available as a combination eye drop with a beta-blocker called timolol, in a brand called Cosopt®.

Before using dorzolamide

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start using the drops it is important that your doctor knows:

  • If you wear soft contact lenses.

  • If you are pregnant or breastfeeding.

  • If you have any problems with the way your kidneys work, or if you have ever had kidney stones.

  • If you have any problems with the way your liver works.

  • If you have a condition where your blood acidity is too high, called hyperchloraemic acidosis.

  • If you have dry eye disease or are using eye drops for dry eyes.

  • If you are taking any medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

  • If you have ever had an allergic reaction to a medicine. It is particularly important that you tell your doctor if you have ever had a bad reaction to any other eye drops, or to a type of medicine known as a 'sulfonamide'.

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How to use dorzolamide eye drops

  1. Wash your hands before you use the drops.

  2. Remove the cap (or the tip of the unit if you are using a single-dose unit).

  3. Tilt your head back a little and pull the lower lid of your eye out to form a pocket.

  4. Hold the bottle (or single-dose unit) upside down near to your eye. Try not to touch your eye as you do this.

  5. Press the container gently to release one drop into your eye. Only use a second drop if the first drop missed going into your eye.

  6. Close your eye for a minute or two, and press gently on the side of your nose where the corner of your eye meets your nose. This helps to stop the drop from draining away and keeps it in your eye.

  7. Repeat the process in your other eye if you have been told to use the drops in both eyes.

  8. Replace the cap (or if you are using the single-dose unit, throw it away).

Getting the most from your treatment

  • Before you start using the eye drops, read the manufacturer's printed information leaflet from the pack. It will give you more information about the eye drops and will provide you with a full list of the side-effects which you may experience from using them.

  • Use one drop into the eye (or eyes) affected. The drops are used two or three times each day, depending on whether you are also using other drops. Your doctor will tell you how many times a day is right for you and your dose will also be printed on the label of the pack.

  • Remember to use the drops at regular intervals and try not to miss any doses. If you do forget to use the drops, put them in as soon as you remember, but do not 'double up' to make up for any missed doses.

  • Take care not to touch the tip of the dropper with your eye, fingers, or any other surface. This is to prevent the drops from becoming contaminated.

  • If you are using any other eye drops, leave 5-10 minutes between applying each one. This is to prevent more liquid going into your eye than it can handle. Otherwise the drops will overflow from your eye and not have the intended effect.

  • When first put in, eye drops can make your eyes water and may sometimes cause blurred vision. If this happens, it should quickly clear. Make sure you can see clearly again before you drive and before you use tools or machines.

  • Do not wear soft contact lenses unless your doctor has advised you otherwise. This is because bottles of eye drops contain preservatives which can affect soft contact lenses. The single-dose units do not contain a preservative.

  • Keep your regular appointments with your doctor and eye clinic so that your progress can be checked.

  • If you are having an operation or any medical treatment, remember to tell the person carrying out the treatment that you are using dorzolamide eye drops.

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Can dorzolamide eye drops cause problems?

Along with their useful effects, eye drops can cause unwanted side-effects although not everyone experiences them. The table below contains the most common ones associated with dorzolamide. You will find a full list in the manufacturer's information leaflet supplied with the drops. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist for further advice if any of the following continue or become troublesome.

Common dorzolamide side-effects

What can I do if I experience this?

Blurred vision, itching or irritation when the drops are first put in

This should quickly ease. If it continues, or if your eye becomes red, painful or inflamed, speak with your doctor as soon as possible


Drink plenty of water and ask your pharmacist to recommend a suitable painkiller. If the headaches continue, let your doctor know

A bitter taste in your mouth, or feelings of sickness (nausea)

Make sure you press gently on the side of your nose (where the corner of your eye meets your nose) for a minute or so after you have used the drops

Feeling tired

If this becomes troublesome, speak with your doctor

Important: bottles of eye drops usually contain preservatives which some people can develop an allergic reaction to. If your eyes or eyelids become red or inflamed after using the drops, contact your doctor for advice. Long-term use of preserved eye drops may lead to eye irritation and symptoms of dry eyes.

How to store dorzolamide

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

  • Bottles of eye drops only keep for four weeks once the bottle has been opened, so do not use the drops if the bottle has been open for longer than this. This will help to prevent the risk of eye infections.

  • Single-dose units should be used as soon as the unit is opened. Do not store or re-use opened units for subsequent doses. This is because the units do not contain any preservative.

Important information about all medicines

Important information about all medicines

If you buy any medicines check with a pharmacist that they are safe to take with your other medicines.

If you suspect that someone has swallowed this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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