Brinzolamide - A review of its use in the management of primary open-angle glaucoma and ocular hypertension

Brinzolamide is a highly specific carbonic anhydrase (CA) inhibitor which lowers intraocular pressure (IOP) by reducing the rate of aqueous humour formation. Formulated as a 1% ophthalmic suspension (Azopt(R)) and administered twice or three times daily, brinzolamide is indicated for the topical management of primary open-angle glaucoma (POAG) and ocular hypertension (OH) as either monotherapy or adjunctive therapy with topical beta-blockers. As monotherapy in patients with POAG or OH, brinzolamide 1% demonstrated IOP-lowering efficacy that was significantly greater than placebo, equivalent to three-times-daily dorzolamide 2% but significantly lower than twice-daily timolol 0.5%. Brinzolamide 1% was equally effective in twice- and three-times-daily regimens producing diurnal mean IOP reductions from baseline in the range of 13.2-21.8%. When used adjunctively twice daily with timolol 0.5%, brinzolamide 1% was as effective as dorzolamide 2% and superior to placebo in lowering IOP in patients with POAG or OH. In clinical trials, brinzolamide 1% was well tolerated causing only nonserious adverse effects that were generally local, transient and mild to moderate in severity. The incidence of the most common adverse events associated with the use of brinzolamide 1% was either similar to (blurred vision and abnormal taste) or significantly lower than (ocular discomfort) with dorzolamide 2%. Topical brinzolamide 1% does not appear to produce the acid-base or electrolyte disturbances and severe systemic adverse effects characteristic of oral CA inhibitors. It can be used in patients unresponsive to beta-blockers or in whom beta-blockers are contraindicated. Brinzolamide 1% administered twice daily is among the least costly alternatives and adjuncts to P-blocker therapy for glaucoma and is generally associated with less direct medical cost than dorzolamide. Conclusion: Brinzolamide 1% ophthalmic suspension administered twice or three times daily, as monotherapy or adjunctive therapy with topical beta-blockers, has good IOP-lowering efficacy in patients with POAG or OH that is equivalent to that of dorzolamide 2% (three times daily as monotherapy, twice daily as adjunctive therapy). Brinzolamide is generally well tolerated and does not produce the systemic adverse effects associated with oral CA inhibitors. It can be used in patients who are unresponsive to, intolerant of, or unable to receive, ophthalmic beta-blockers. Thus, brinzolamide, either as monotherapy or adjunctive therapy with topical beta-blockers, should be regarded as a good second-line option in the pharmacological management of POAG and OH, and may be preferred over dorzolamide because of significantly less ocular discomfort.