COSOPT

What it is

COSOPT is dorzolamide hydrochloride and timolol maleate eye drops. COSOPT is supplied as a sterile, isotonic, buffered, slightly viscous, aqueous solution containing 20.00 mg (2.0% w/v) dorzolamide and 5.00 mg (0.5% w/v) timolol as the active ingredients. It is presented as eye drops in the pharmaceutical form of a clear, slightly viscous, colourless aqueous solution. COSOPT is comprised of a topical carbonic anhydrase inhibitor and a topical beta-adrenergic receptor blocking agent. Each of these two components decreases elevated intraocular pressure by reducing aqueous humour secretion, but does so by a different mechanism of action.

Approved indications

— Treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma when concomitant therapy is appropriate.

Dosing overview

The dose is one drop of COSOPT in the affected eye(s) two times daily. If another topical ophthalmic agent is being used, COSOPT and the other agent should be administered at least ten minutes apart.

Key safety warnings

The timolol component is a beta-blocker and although administered topically, is absorbed systemically, so the same types of adverse reactions found with systemic administration of beta-blockers may occur with topical administration. Respiratory reactions and cardiac reactions, including death due to bronchospasm in patients with asthma and rarely death in association with cardiac failure, have been reported following administration of timolol maleate ophthalmic solution. The dorzolamide component is a sulfonamide and although administered topically, is absorbed systemically, so the same types of adverse reactions found with systemic administration of sulfonamides may occur with topical administration, such as Stevens-Johnson syndrome and toxic epidermal necrolysis. COSOPT contains benzalkonium chloride, which has been reported to cause eye irritation, symptoms of dry eyes and may affect the tear film and corneal surface, and should be used with caution in dry eye patients and in patients where the cornea may be compromised.

Contraindications

COSOPT is contraindicated in patients with reactive airway disease, bronchial asthma or a history of bronchial asthma, or severe chronic obstructive pulmonary disease; sinus bradycardia, sick sinus syndrome, sino-atrial block, second or third degree atrioventricular block, overt cardiac failure, cardiogenic shock; or hypersensitivity to any component of this product. Dorzolamide has not been studied in patients with severe renal impairment (CrCl < 30 millilitre/min) or with hyperchloremic acidosis, and because dorzolamide hydrochloride and its metabolite are excreted predominantly by the kidney, dorzolamide is therefore contraindicated in such patients.

Regulatory history

COSOPT dorzolamide hydrochloride 20 mg and timolol maleate 5 mg per mL eye drop bottle was first listed on the ARTG on 1999-09-02. A preservative-free variant, COSOPT PRESERVATIVE-FREE dorzolamide (as hydrochloride) 20 mg/mL and timolol (as maleate) 5 mg/mL single dose eye drop ampoule, was first listed on 2011-04-07.