Currently Enrolling Trials
Cosopt is a carbonic anhydrase inhibitor with a beta-adrenergic receptor blocking agent.
Cosopt is specifically indicated for the reduction of elevated intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension who are insufficiently responsive to beta-blockers.
Cosopt is supplied as an ophthalmologic solution containing 20 mg/mL dorzolamide and 5 mg/mL timolol. The dose is one drop of Cosopt in the affected eye(s) two times daily.
Mechanism of Action
Cosopt is comprised of two components: dorzolamide hydrochloride and timolol maleate. Each of these two components decreases elevated intraocular pressure, whether or not associated with glaucoma, by reducing aqueous humor secretion.
Dorzolamide hydrochloride is an inhibitor of human carbonic anhydrase II. Inhibition of carbonic anhydrase 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.
Timolol maleate is a beta1 and beta2 (non-selective) adrenergic receptor blocking agent that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anesthetic (membrane-stabilizing) activity.
The combined effect of these two agents administered as Cosopt twice daily results in additional intraocular pressure reduction compared to either component administered alone, but the reduction is not as much as when dorzolamide administered three times daily and timolol twice daily are administered concomitantly.
Adverse effects associated with the use of Cosopt may include the following:
- taste perversion (bitter, sour, or unusual taste)
- ocular burning and/or stinging
- conjunctival hyperemia
- blurred vision
- superficial punctate keratitis or eye itching
Clinical Trial Results
In clinical studies, Cosopt administered twice a day produced reduction in intraocular pressure greater than that seen when either Trusopt or Timoptic was used as sole therapy. The reduction was slightly less than that seen when both were used individually in a concomitant daily treatment regimen of Trusopt three times daily and Timoptic twice daily.