Dorzolamide

What it is and how it works

Mechanism of Action Dorzolamide hydrochloride and timolol maleate ophthalmic solution is comprised of two components: Dorzolamide hydrochloride and timolol maleate. Each of these two components decreases elevated intraocular pressure, whether or not associated with glaucoma, by reducing aqueous humor secretion. Elevated intraocular pressure is a major risk factor in the pathogenesis of optic nerve damage and glaucomatous visual field loss. The higher the level of intraocular pressure, the greater the likelihood of glaucomatous field loss and optic nerve damage. Dorzolamide hydrochloride is an inhibitor of human carbonic anhydrase II.

Indications

Dorzolamide hydrochloride and timolol maleate ophthalmic solution is indicated for the reduction of elevated intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension who are insufficiently responsive to beta-blockers (failed to achieve target IOP determined after multiple measurements over time). The IOP-lowering of dorzolamide hydrochloride and timolol maleate ophthalmic solution administered twice a day was slightly less than that seen with the concomitant administration of 0.5% timolol administered twice a day and 2% dorzolamide administered three times a day . Dorzolamide hydrochloride and timolol maleate ophthalmic solution is a combination of dorzolamide hydrochloride, a carbonic anhydrase inhibitor, and timolol maleate, a beta-adrenergic receptor blocking agent, indicated for the reduction of elevated intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension who are insufficiently responsive to beta-blockers.

Dosage and administration (summary)

The dose is one drop of dorzolamide hydrochloride and timolol maleate ophthalmic solution in the affected eye(s) two times daily. If more than one topical ophthalmic drug is being used, the drugs should be administered at least five minutes apart . The dose is one drop of dorzolamide hydrochloride and timolol maleate ophthalmic solution in the affected eye(s) two times daily.

Contraindications

Dorzolamide hydrochloride and timolol maleate ophthalmic solution is contraindicated in patients with: Bronchial asthma or a history of bronchial asthma, severe chronic obstructive pulmonary disease. Sinus bradycardia, second or third degree atrioventricular block, overt cardiac failure, cardiogenic shock. Hypersensitivity to any component of this product.

Warnings and precautions

Potentiation of Respiratory Reactions Including Asthma Cardiac Failure Sulfonamide Hypersensitivity Obstructive Pulmonary Disease Increased Reactivity to Allergens Potentiation of Muscle Weakness Masking of Hypoglycemic Symptoms in Patients with Diabetes Mellitus Masking of Thyrotoxicosis Renal and Hepatic Impairment Impairment of Beta-Adrenergically Mediated Reflexes During Surgery Potentiation of Respiratory Reactions Including Asthma Dorzolamide hydrochloride and timolol maleate ophthalmic solution contains timolol maleate, a beta-adrenergic blocking agent.

Pregnancy

Pregnancy Teratogenic Effects . Developmental toxicity studies with dorzolamide hydrochloride in rabbits at oral doses of ≥ 2.5 mg/kg/day (37 times the recommended human ophthalmic dose) revealed malformations of the vertebral bodies.

Storage and supply

Dorzolamide hydrochloride and timolol maleate ophthalmic solution, USP 2%/0.5% is supplied in 10mL a natural, LDPE plastic ophthalmic dispenser with a natural nozzle and a dark blue, tamper-evident cap. NDC 71921-226-10, 10 mL in a 10 mL capacity bottle.

Source: Dorzolamide Hydrochloride Timolol Maleate (Dorzolamide Hydrochloride Timolol Maleate) — US FDA prescribing information, 2026-06-12, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.