Dorzolamide

Topical carbonic anhydrase II inhibitor for ophthalmic use

ATC code: S01EC03

Brand names: Trusopt, Cosopt

Updated 24 Sep 2026 · Methodology

Indications

Open-angle glaucoma

Second line

Dorzolamide is a second-line topical carbonic anhydrase inhibitor for primary open-angle glaucoma. EGS 2024 and SEG/SEO 2023 recommend it as monotherapy for patients with contraindications to prostaglandins and beta blockers or as add-on when IOP control is insufficient. IOP reduction of 14–20% is weaker than with prostaglandins. Frequently used in a fixed combination with timolol (Cosopt) for two-mechanism synergy.

Sources

ICD-10: H40.1 · ICD-11: 9C61.0

Ocular hypertension

Second line

Dorzolamide lowers IOP in ocular hypertension when prostaglandins and beta blockers are contraindicated or do not reach target reduction. EGS 2024 positions it as second-line monotherapy or add-on.

Sources

ICD-10: H40.0 · ICD-11: 9C61.01

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Vision improvement and retinal nutrition marketing

Not recommended

Dorzolamide is a topical carbonic anhydrase inhibitor and AEMPS registered it solely for IOP lowering. Marketing as a drug that «improves vision» or «nourishes the retina» has no evidence base: dorzolamide affects only aqueous production and does not change visual acuity, visual fields or exert RCT-confirmed neuroprotection. Off-label use for cystoid macular oedema after cataract surgery (CME) has weak evidence – case series and small open trials, without large RCTs (Cochrane 2018). It does not work in macular oedema of other aetiologies. If dorzolamide was suggested «for vision» or «for the retina» without a diagnosis of glaucoma or ocular hypertension, consider seeking a second opinion.

Sources

How to read tiers A–F

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit

Mechanism of action

Selective inhibitor of carbonic anhydrase isoenzyme II in the ciliary body. Blocks bicarbonate formation needed for aqueous humour secretion and reduces production by 30–50%. Instillation of a 2% solution 2–3 times daily lowers IOP by 14–20% from baseline. Activity depends solely on reduced secretion, not on outflow. Systemic absorption is minimal, but accumulation may occur in severe renal impairment (CrCl below 30 mL/min).

Safety

Contraindications

Hypersensitivity to dorzolamide or sulphonamides
Severe renal impairment (CrCl under 30 mL/min)
Hyperchloraemic acidosis
Under 1 year of age without paediatric supervision

Serious adverse effects

Stevens-Johnson hypersensitivity reactions in patients with sulphonamide allergy
Corneal decompensation in patients with endothelial dystrophy
Iridocyclitis
Systemic effects (urolithiasis, metabolic acidosis) in renal impairment

Common adverse effects

Burning and stinging after instillation
Bitter metallic taste
Superficial punctate keratitis
Tearing
Conjunctivitis
Allergic blepharitis

Pregnancy: can you take Dorzolamide?

AEMPS summary of product characteristics (section 4.6): dorzolamide should not be used during pregnancy. There are no adequate clinical data in pregnant women, and in rabbits dorzolamide was teratogenic at maternally toxic doses.

Breastfeeding: can you take Dorzolamide?

Compatible with caution. Hale L3. Systemic absorption from ophthalmic instillation is modest. Milk concentrations have not been studied. Punctal occlusion for 1–2 minutes after instillation reduces infant exposure.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Label mentions7 mentions

Verbatim lines from the interaction sections, in the language of the label

From this drug’s label

MinorAcetylsalicylic acid
«- fármacos sistémicos, incluidos los inhibidores de la ECA, bloqueadores de los canales de calcio, diuréticos, fármacos antiinflamatorios no esteroideos (incluido el ácido acetilsalicílico), y…»
AEMPS, section 4.5 · Open on CIMA
MinorAINEclass named in the label
«- fármacos sistémicos, incluidos los inhibidores de la ECA, bloqueadores de los canales de calcio, diuréticos, fármacos antiinflamatorios no esteroideos (incluido el ácido acetilsalicílico), y…»
AEMPS, section 4.5 · Open on CIMA
Minordiuréticosclass named in the label
«- fármacos sistémicos, incluidos los inhibidores de la ECA, bloqueadores de los canales de calcio, diuréticos, fármacos antiinflamatorios no esteroideos (incluido el ácido acetilsalicílico), y…»
AEMPS, section 4.5 · Open on CIMA
Minorinhibidores de la ECAclass named in the label
«- fármacos sistémicos, incluidos los inhibidores de la ECA, bloqueadores de los canales de calcio, diuréticos, fármacos antiinflamatorios no esteroideos (incluido el ácido acetilsalicílico), y…»
AEMPS, section 4.5 · Open on CIMA
MinorInsulin
«- fármacos sistémicos, incluidos los inhibidores de la ECA, bloqueadores de los canales de calcio, diuréticos, fármacos antiinflamatorios no esteroideos (incluido el ácido acetilsalicílico), y…»
AEMPS, section 4.5 · Open on CIMA
Minorinsulinaclass named in the label
«- fármacos sistémicos, incluidos los inhibidores de la ECA, bloqueadores de los canales de calcio, diuréticos, fármacos antiinflamatorios no esteroideos (incluido el ácido acetilsalicílico), y…»
AEMPS, section 4.5 · Open on CIMA
MinorTimolol
«- timolol solución oftálmica,»
AEMPS, section 4.5 · Open on CIMA

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Frequently asked

What is Dorzolamide used for?

Dorzolamide is evaluated for the following indications with varying evidence strength: Open-angle glaucoma (evidence tier A), Ocular hypertension (evidence tier B), Vision improvement and retinal nutrition marketing (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Dorzolamide?

Common side effects of Dorzolamide (≥ 1 in 100): Burning and stinging after instillation, Bitter metallic taste, Superficial punctate keratitis, Tearing, Conjunctivitis, Allergic blepharitis. See the Safety section for uncommon and serious reactions.

Is Dorzolamide safe during pregnancy?

Is Dorzolamide compatible with breastfeeding?

Who should not take Dorzolamide?

Dorzolamide is contraindicated in: Hypersensitivity to dorzolamide or sulphonamides; Severe renal impairment (CrCl under 30 mL/min); Hyperchloraemic acidosis; Under 1 year of age without paediatric supervision. Full list in the Safety section.

Official sources

Direct links to regulator labels. Open in a new tab.

AEMPS / CIMA
FDA / DailyMedLabel dated 10/04/2024

Other drugs in this group

Hypromellose, Latanoprost, Lutein + zeaxanthin, Tetryzoline, Travoprost, Brimonidine, Timolol, Bimatoprost