Dorzolamide

Ophthalmic
Open-angle glaucoma, Ocular hypertension, Pseudoexfoliation glaucoma
Adult: As monotherapy in patients unresponsive to β-blockers or in whom β-blockers are contraindicated: As 2% eye drop solution: Instil 1 drop into the conjunctival sac of affected eye(s) tid. As an adjunct to β-blockers: As 2% eye drop solution: Instil 1 drop into the conjunctival sac of the affected eye(s) bid.
Renal impairment:

CrCl (ml/min)	Dosage Recommendation
<30	Contraindicated.

Hyperchloraemic acidosis. Severe renal impairment.

Patient with history of renal calculi, pre-existing chronic corneal defects, history of intraocular surgery, low endothelial cell counts. Hepatic impairment. Pregnancy and lactation. Patient Counselling This drug may cause dizziness or visual disturbances, if affected, do not drive or operate machinery. Remove contact lenses before administration and reinsert them after at least 15 minutes. Monitoring Parameters Perform ophthalmic exams (e.g. optic nerve and visual field assessment). Obtain serial measurement of IOP.

Significant: Bacterial keratitis; local ocular effects, conjunctivitis, lid reactions (chronic administration); choroidal detachment (after filtration procedures); corneal oedema. Rarely, urolithiasis. Eye disorders: Burning sensation, stinging of eyes, blurred vision, eye itching, superficial punctate keratitis, tearing. Gastrointestinal disorders: Bitter taste, nausea. General disorders and administration site conditions: Fatigue, asthenia. Nervous system disorders: Headache.
Potentially Fatal: Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis; blood dyscrasias (e.g. agranulocytosis, aplastic anaemia).

Symptoms: Nausea, dizziness, headache, fatigue, dysphagia, abnormal dreams; electrolyte imbalance, acidotic state. Management: Symptomatic and supportive treatment. Monitor electrolyte levels (especially K) and blood pH levels.

May have an additive effect with oral carbonic anhydrase inhibitors. May increase the risk of acid-base and electrolyte disturbances with high-dose salicylate therapy.

Dorzolamide is a carbonic anhydrase inhibitor. It reversibly inhibits carbonic anhydrase II and IV found in the ciliary epithelium. This results in the decrease of hydrogen ion secretion at the renal tubule and an increase in the renal excretion of Na, K, bicarbonate, and water leading to the reduction of aqueous humour production, thus decreasing intraocular pressure (IOP).
Duration: 8-12 hours.
Absorption: Systemically absorbed after topical application.
Distribution: Accumulates in RBCs (chronic dosing). Plasma protein binding: Approx 33%.
Metabolism: Metabolised into a single N-desethyl metabolite (less active than parent drug).
Excretion: Via urine (as unchanged drug and metabolite).

Ophthalmic: Store below 30°C. Protect from light.

Antiglaucoma Preparations

S01EC03 - dorzolamide ; Belongs to the class of carbonic anhydrase inhibitors. Used in the treatment of glaucoma.