dorzolamide (Trusopt)

Dorzolamide is an ophthalmic solution (a liquid that is placed in the eyes) that is used for treating glaucoma. It is in a class of drugs called carbonic anhydrase inhibitors which also includes brinzolamide (Azopt). Many parts of the body, including the eye, contain the enzyme carbonic anhydrase. Carbonic anhydrase controls secretion of fluid within the eye and thereby determines the pressure within the eye (intraocular pressure); the greater the amount of fluid that is secreted, the higher the pressure. Patients with glaucoma have increased intraocular pressure. Dorzolamide blocks carbonic anhydrase thereby decreasing secretion of fluid and intraocular pressure. This reduces the risk of nerve damage and loss of vision that is caused by increased intraocular pressure in patients with glaucoma. The FDA approved dorzolamide in December 1994.

What brand names are available for dorzolamide?

Trusopt

Is dorzolamide available as a generic drug?

Yes

Do I need a prescription for dorzolamide?

Yes

The most common side effects of dorzolamide include:

• irritation,
• eye burning,
• eye stinging,
• discomfort of the eye.

These effects generally are temporary and occur immediately after administration. Approximately 1 in 4 patients complain of a bitter taste, and 1 in 10 patients experience an allergic eye reaction or eye inflammation (superficial punctate keratitis).

Other important, but less common side effects include:

• blurred vision,
• excessive tearing,
• dry eyes, and
• increased sensitivity to light.

Bacterial infections of the eye have been reported and may be due to accidental contamination of the containers with bacteria during handling. Dorzolamide is a sulfonamide and can be absorbed into the body. Individuals who are allergic to sulfonamides may react to dorzolamide. Therefore, dorzolamide should not be administered to patients with allergies to sulfonamides, and it can cause some of the side effects of sulfonamides. Severe skin reactions also have been reported.

The usual dose is one drop into the affected eye(s) three times daily.

Patients should wash both hands before each use of dorzolamide or any other eye medication to prevent contamination of the eye. Contact lenses should be removed since dorzolamide solution contains benzalkonium chloride which can be absorbed by contact lenses. The head is tilted back, and the lower eyelid is pulled down with the index finger to form a pouch. The bottle is squeezed slightly to allow the prescribed number of drops into the pouch. The tip of the dropper should not touch the eye or eyelid. The eye then is closed gently for one to two minutes without blinking.

Dorzolamide should not be administered with oral carbonic anhydrase inhibitors because the combination may lead to increased adverse effects. When used with other eye drops for reducing intraocular pressure, administration of both drugs should be separated by at least10 minutes.

It is not known if dorzolamide is excreted into breast milk.

What preparations of dorzolamide are available?

Ophthalmic solution 2%: 10 ml.

How should I keep dorzolamide stored?

Dorzolamide should be kept at room temperature, 15 C to 30 C (59 F to 86 F), and protected from direct light.