indication

For the treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma. Also used prophylatically for the inhibition of perioperative IOP increase (before neodynium yttrium aluminum garnet laser posterior capsulotomy).

pharmacology

Dorzolamide is topical CA inhibitor that is indicated for the reduction of elevated IOP in patients with open-angle glaucoma or ocular hypertension who are insufficiently responsive to beta-blockers. Dorzolamide reduces IOP by approximately 17-23% in patients with elevater IOP.

mechanism of action

Dorzolamide is a sulfonamide and a highly specific carbonic anhydrase II (CA-II) inhibitor, which is the main CA isoenzyme involved in aqueous humor secretion. Inhibition of CA-II in the ciliary processes of the eye decreases aqueous humor secretion, presumably by slowing the formation of bicarbonate ions with subsequent reduction in sodium and fluid transport. Dorzolamide also accumulates in red blood cells as a result of CA-II binding, as CA-II is found predominantly in erythrocytes. However, sufficient CA-II activity remains so that adverse effects due to systemic CA inhibition are not observed.

toxicity

Dizziness, headache, shortness of breath, slow heartbeat, severe asthma, cardiac arrest

half life

4 months

route of elimination

Dorzolamide is primarily excreted unchanged in the urine; the metabolite also is excreted in urine.