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dorzolamide (Trusopt)

Tradename: Trusopt. Indications: 1) open-angle glaucoma 2) ocular hypertension Contraindications: Caution: 1) not recommended for patients with severe renal insufficiency (creatinine clearance < 30 mL/min) 2) use with caution in patients with hepatic impairment 3) sulfonamide hypersenstivity 4) bacterial keratitis 5) acute angle-closure glaucoma Pregnancy category: C Lactation: not known whether dorzolamide is secreted in human milk Dosage: - 1 drop OU TID. 2% (5 & 10 mL) Preservative is benzalkonium chloride. Storage: 10-25 C Pharmacokinetics: - systemic absorption occurs with topical administration - dorzolamide 2% OU TID achieves blood levels similar to dorzolamide 2 mg PO BID [4] - blood levels below that anticipated for a pharmacologic effect on renal function or respiratory function [4] - accumulates in erythrocytes with chronic dosing - 1/2life (phase 2) of erythrocyte elimination is 4 months - 33% binding to plasma proteins - excreted largely unchanged in the urine Monitor: - K+, blood pH (or CO2), intraocular pressure Adverse effects: 1) common (> 10%) - bitter taste (25%), burning, stinging, irritation (up to 33%), ocular allergic reaction (10%) superficial punctate keratitis (10-15%) 2) less common (5-10%) - blurred vision, tearing, dryness, photophobia 3) uncommon (< 1%) - headache, asthenia, fatigue, nausea, urolithiasis, iridocyclitis 4) other - corneal edema [4] - conjunctivitis Drug interactions: 1) avoid concurrent administration of oral carbonic anhydrase inhibitors 2) salicylate may increase toxicity Mechanism of action: 1) inhibits carbonic anhydrase 2) produces mean reduction in intraocular pressure of 1-23% (3-5 mm Hg) dosed TID [4]

Interactions

drug interactions drug adverse effects (more general classes) monitor with carbonic anhydrase inhibitors

Related

benzalkonium (Zephiran, Sterinol)

General

carbonic anhydrase inhibitor sulfonamide

Properties

INHIBITS: carbonic anhydrase (dehydratase) MISC-INFO: pregnancy-category C safety in lactation -

Database Correlations

PUBCHEM correlations

References

  1. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
  2. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
  3. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  4. Dorzolamide Hydrochloride Ophthalmic Solution 2% Package Insert Hi-Tech Pharmaceutical Company Amityville, NY 11701

Component-of

dorzolamide/timolol (Cosopt)