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Generic name: dorzolamide ophthalmic

Brand names: Trusopt

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Solution, Ophthalmic:

Trusopt: 2% (10 mL)

Generic: 2% (10 mL)


Mechanism of Action

Reversible inhibition of the enzyme carbonic anhydrase II and IV in the ciliary epithelium resulting in reduction of hydrogen ion secretion at renal tubule and an increased renal excretion of sodium, potassium, bicarbonate, and water to decrease production of aqueous humor to reduce intraocular pressure.



Topical: Reaches systemic circulation where it accumulates in RBCs during chronic dosing as a result of binding to CA-II


In RBCs during chronic administration


To N-desethyl metabolite (less potent than parent drug)


Urine (as unchanged drug and metabolite, N-desethyl)

Duration of Action

8 to 12 hours

Half-Life Elimination

Terminal RBC half-life: 147 days; washes out of RBCs nonlinearly, resulting in a rapid decline of drug concentration initially, followed by a slower elimination phase with a half-life of about 4 months

Protein Binding


Use: Labeled Indications

Ocular hypertension/glaucoma (open-angle): Treatment of elevated intraocular pressure.


Hypersensitivity to dorzolamide or any component of the formulation

Dosage and Administration

Dosing: Adult

Ocular hypertension/glaucoma (open-angle): Ophthalmic: Instill 1 drop in the affected eye(s) 3 times daily.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Reduction of intraocular pressure: Infants, Children, and Adolescents: Ophthalmic: 1 drop to affected eye(s) 3 times/daily


Ophthalmic: If more than one topical ophthalmic drug is being used, administer the drugs at least 5 minutes apart. Remove contact lens prior to administration and wait 15 minutes before reinserting. Avoid allowing the tip of the dispensing container to contact the eye or surrounding structures. Use eyelid closure or nasolacrimal occlusion when applying topical medications to reduce systemic absorption.


Store at 15°C to 30°C (59°F to 86°F). Protect from light.

Drug Interactions

Alpha-/Beta-Agonists (Indirect-Acting): Carbonic Anhydrase Inhibitors may increase the serum concentration of Alpha-/Beta-Agonists (Indirect-Acting). Monitor therapy

Amantadine: Carbonic Anhydrase Inhibitors may increase the serum concentration of Amantadine. Monitor therapy

Carbonic Anhydrase Inhibitors: May enhance the adverse/toxic effect of other Carbonic Anhydrase Inhibitors. The development of acid-base disorders with concurrent use of ophthalmic and oral carbonic anhydrase inhibitors has been reported. Management: Avoid concurrent use of different carbonic anhydrase inhibitors if possible. Monitor patients closely for the occurrence of kidney stones and with regards to severity of metabolic acidosis. Avoid combination

Adverse Reactions

Frequency not always defined.

Dermatologic: Skin rash

Gastrointestinal: Bitter taste (~25% following administration), fatigue, headache, nausea

Genitourinary: Urolithiasis

Hypersensitivity: Local ocular hypersensitivity reaction (~10%)

Neuromuscular & skeletal: Weakness

Ocular: Burning sensation of eyes (~33%), eye discomfort (~33%), stinging of eyes (~33%), superficial punctate keratitis (10% to 15%), blurred vision (1% to 5%), conjunctivitis (1% to 5%), eyelid irritation (1% to 5%), eye redness (1% to 5%), lacrimation (1% to 5%), photophobia (1% to 5%), xerophthalmia (1% to 5%), iridocyclitis

<1%, postmarketing and/or case reports: Angioedema, bronchospasm, choriodal detachment (following filtration procedures), contact dermatitis, crusting of eyelid, dizziness, dyspnea, epistaxis, myopia (transient), ocular pain, paresthesia, pruritus, Stevens-Johnson syndrome, throat irritation, toxic epidermal necrolysis, urticaria, xerostomia


Concerns related to adverse effects:

  • Bacterial keratitis: Inadvertent contamination of multiple-dose ophthalmic solutions has caused bacterial keratitis.
  • Ocular effects: Local ocular adverse effects (primarily conjunctivitis and lid reactions) were reported with chronic administration; many resolved upon discontinuation of drug therapy. Choroidal detachment has been reported after filtration procedures.
  • Sulfonamide (“sulfa”) allergy: Dorzolamide is a sulfonamide; although administered ocularly, systemic absorption may occur and could result in hypersensitivity. Discontinue use if signs of hypersensitivity or a serious reaction occur.
  • Systemic effects: Systemic absorption and adverse effects (similar to sulfonamides) including, blood dyscrasias, Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias may occur with ophthalmic use.

Disease-related concerns:

  • Corneal endothelium: Use with caution in patients with low endothelial cell counts; may be at increased risk of corneal edema.
  • Hepatic impairment: Use with caution in patients with hepatic impairment (has not been studied).
  • Renal impairment: Use is not recommended in patients with severe renal impairment (CrCl <30 mL/minute) (has not been studied).

Concurrent drug therapy issues:

  • Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed.

Special populations:

  • Contact lens wearers: Some products contain benzalkonium chloride which may be absorbed by soft contact lenses; remove lens prior to administration and wait 15 minutes before reinserting.

Other warnings/precautions:

  • Appropriate use: Should be used in combination with therapeutic interventions for the treatment of acute angle-closure glaucoma.

Monitoring Parameters

Ophthalmic exams (optic nerve and visual field assessment), serial measurement of intraocular pressure (IOP). Frequency of follow up based upon whether target IOP achieved, if there is any progression of damage, and how long disease has been controlled (AAO 2019).


Pregnancy Risk Factor


Pregnancy Considerations

Adverse events have been observed in animal reproduction studies following systemic administration. IOP is usually lower during pregnancy. If topical medications for the treatment of glaucoma in pregnant women cannot be discontinued because small increases in IOP cannot be tolerated, the minimum effective dose should be used in combination with punctal occlusion to decrease exposure to the fetus (Johnson, 2001).

Patient Education

What is this drug used for?

  • It is used to treat glaucoma.
  • It is used to lower high eye pressure.

Frequently reported side effects of this drug

  • Blurred vision
  • Burning
  • Stinging
  • Bad taste
  • Dry eyes
  • Watery eyes
  • Sensitivity to lights

Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:

  • Vision changes
  • Eye pain
  • Severe eye irritation
  • Edema of eye or eyelid
  • Severe sulfonamide reaction like rash; red, swollen, blistered, or peeling skin; red or irritated eyes; mouth, throat, nose, or eye sores; fever, chills, or sore throat
  • Cough that is new or worse
  • Loss of strength and energy
  • Any bruising or bleeding
  • Liver problems like dark urine, fatigue, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or yellow skin.
  • Signs of a significant reaction like wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Source: Wolters Kluwer Health. Last updated January 23, 2020.