Dorzolamide is a topical, potent, and reversible inhibitor of carbonic anhydrase II (CA-II), used primarily as an ophthalmic solution for the reduction of elevated intraocular pressure (IOP) in patients with ocular hypertension or open-angle glaucoma. It decreases aqueous humor production by the ciliary processes in the eye. In the Indian context, it is a first-line or adjunctive therapy, widely available and cost-effective.
Adult: One drop in the affected eye(s) 3 times daily. Often used as twice daily (BID) in fixed-dose combinations (e.g., with Timolol).
Note: 1. Wash hands. 2. Tilt head back. 3. Gently pull lower eyelid to form a pouch. 4. Instill one drop. 5. Close eye gently for 1-2 minutes, apply gentle pressure to the nasolacrimal duct (inner corner of eye) to minimize systemic absorption. 6. Do not touch dropper tip to any surface. 7. Wait at least 10 minutes before instilling any other ophthalmic product.
Dorzolamide is a sulfonamide derivative that inhibits carbonic anhydrase isoenzyme II (CA-II), which is found in high concentration in the ciliary processes of the eye. Inhibition of CA-II reduces the formation of bicarbonate ions, leading to a reduction in sodium and fluid transport. This results in a decrease in aqueous humor secretion and a subsequent reduction in intraocular pressure (IOP).
Pregnancy: Category C: Animal studies have shown teratogenicity (forelimb malformations). There are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.
Driving: May cause transient blurred vision immediately after instillation. Patients should not drive or use machines until vision clears.
| Oral Carbonic Anhydrase Inhibitors (Acetazolamide, Methazolamide) | Additive systemic effects, increasing risk of metabolic acidosis and electrolyte disturbances. | Major |
| High-dose Salicylates (Aspirin) | May displace dorzolamide from erythrocyte binding sites, potentially increasing systemic levels and toxicity. Risk of acidosis. | Moderate |
| Other Topical Beta-blockers (Timolol, Betaxolol) - when used separately | Additive IOP-lowering effect. Fixed-dose combinations exist to improve compliance. | Moderate |
| Drugs causing Hypokalemia (Diuretics, Amphotericin B) | Additive risk of hypokalemia due to systemic bicarbonate loss. | Moderate |
Same composition (Dorzolamide (2% w/v)), different brands: