Dorzolamide, sold under the brand name Trusopt among others, is a medication used to treat high pressure inside the eye, including in cases of

glaucoma Glaucoma is a group of eye diseases that result in damage to the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, in which the drainage angle for fluid within the eye re ...

. It is used as an eye drop. Effects begin within three hours and last for at least eight hours. It is also available as the combination

dorzolamide/timolol Dorzolamide/timolol, sold under the brand name Cosopt among others, is a medication used to treat high pressure inside the eye including glaucoma. It is a combination of dorzolamide hydrochloride and timolol maleate. It may be used when a be ...

. Common side effects include eye discomfort, eye redness, taste changes, and blurry vision. Serious side effects include Steven Johnson syndrome. Those allergic to

sulfonamides In organic chemistry, the sulfonamide functional group (also spelled sulphonamide) is an organosulfur group with the structure . It consists of a sulfonyl group () connected to an amine group (). Relatively speaking this group is unreactive. ...

may be allergic to dorzolamide. Use is not recommended in

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ...

breastfeeding Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that bre ...

. It is a

carbonic anhydrase inhibitor Carbonic anhydrase inhibitors are a class of pharmaceuticals that suppress the activity of carbonic anhydrase. Their clinical use has been established as anti-glaucoma agents, diuretics, antiepileptics, in the management of mountain sickness, g ...

and works by decreasing the production of

aqueous humour The aqueous humour is a transparent water-like fluid similar to plasma, but containing low protein concentrations. It is secreted from the ciliary body, a structure supporting the lens of the eyeball. It fills both the anterior and the posteri ...

. Dorzolamide was approved for medical use in the United States in 1994. It is available as a

generic medication A generic drug is a pharmaceutical drug that contains the same chemical substance as a drug that was originally protected by chemical patents. Generic drugs are allowed for sale after the patents on the original drugs expire. Because the active c ...

. In 2020, it was the 216th most commonly prescribed medication in the United States, with more than 2million prescriptions. It is a second-generation carbonic anhydrase inhibitor.

Medical uses

Dorzolamide hydrochloride is used to lower excessive

intraocular pressure Intraocular pressure (IOP) is the fluid pressure inside the eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response fu ...

in open-angle

and ocular hypertension. This drug is able to cross the cornea, reach the ciliary body of the eye, and produce systemic effects on the carbonic anhydrase enzyme within the eye.

Side effects

Ocular stinging, burning, itching and bitter taste. It causes shallowing of the anterior chamber and leads to transient

myopia Near-sightedness, also known as myopia and short-sightedness, is an eye disease where light focuses in front of, instead of on, the retina. As a result, distant objects appear blurry while close objects appear normal. Other symptoms may include ...

. As a second generation carbonic anhydrase inhibitor, Dorzolamide avoids systemic effects associated with first generation carbonic anhydrase inhibitors such as Acetazolamide, Methazolamide, and Dichlorphenamide.

Pharmacodynamics

Dorzolamide lowers

by about 20%. Normally,

carbonic anhydrase The carbonic anhydrases (or carbonate dehydratases) () form a family of enzymes that catalyze the interconversion between carbon dioxide and water and the dissociated ions of carbonic acid (i.e. bicarbonate and hydrogen ions). The active si ...

converts carbonic acid () into

bicarbonate In inorganic chemistry, bicarbonate ( IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula . Bicarbonate serves a crucial bioch ...

(), releasing a proton (H⁺) into solution. The H⁺ is then exchanged for sodium (Na⁺) ions, which facilitates the production of aqueous humor . By blocking the function of carbonic anhydrase, the Na⁺/H⁺ exchange is unable to occur, which leads to a decrease in Na⁺ in the cell and prevents aqueous humor production .

History

This drug, developed by Merck, was the first drug in human therapy (market introduction 1995) that resulted from structure-based

drug design Drug design, often referred to as rational drug design or simply rational design, is the inventive process of finding new medications based on the knowledge of a biological target. The drug is most commonly an organic small molecule that ac ...

. It was developed to circumvent the systemic side effects of

acetazolamide Acetazolamide, sold under the trade name Diamox among others, is a medication used to treat glaucoma, epilepsy, altitude sickness, periodic paralysis, idiopathic intracranial hypertension (raised brain pressure of unclear cause), urine alka ...

which has to be taken orally.

Medical uses

Side effects

Pharmacodynamics

History

References

Further reading