What are the dosing, administration guidelines, contraindications, and common adverse effects of Azopt (brinzolamide) eye drops for an adult with open‑angle glaucoma or ocular hypertension?

Azopt (Brinzolamide) Eye Drops: Clinical Guide

Dosing and Administration

Azopt (brinzolamide 1% ophthalmic suspension) should be instilled as one drop in the affected eye(s) three times daily for the treatment of elevated intraocular pressure in open-angle glaucoma or ocular hypertension. 1

• Twice-daily dosing produces mean IOP reductions of 3.4–4.1 mm Hg (13.2–16.7% reduction), while three-times-daily dosing achieves 4.1–4.8 mm Hg reductions (16.6–19.1% reduction). 2
• The three-times-daily regimen is FDA-approved and provides optimal efficacy, though twice-daily dosing demonstrates clinical equivalence in many patients. 1, 2
• When using multiple topical ophthalmic medications, separate administration by at least 10 minutes to prevent washout and ensure adequate drug absorption. 1

Role in Glaucoma Treatment Algorithm

Brinzolamide is a topical carbonic anhydrase inhibitor that reduces IOP by 15–20% through decreased aqueous humor production. 3

Prostaglandin analogs remain first-line therapy for open-angle glaucoma due to superior efficacy (20–35% IOP reduction), once-daily dosing, and excellent tolerability. 3, 4, 5

Brinzolamide serves as an effective second-line agent or adjunctive therapy when:

• Prostaglandin analogs are contraindicated, not tolerated, or refused by the patient 3
• Monotherapy fails to achieve target IOP (typically 20% reduction from baseline) 5
• Beta-blockers are contraindicated due to asthma, COPD, or other pulmonary disease 5

As adjunctive therapy with timolol 0.5%, brinzolamide produces additive IOP-lowering effects that are statistically equivalent to dorzolamide 2% combination therapy. 6, 2

Contraindications

The only absolute contraindication is hypersensitivity to any component of the product, including sulfonamide allergy. 3, 1

• Brinzolamide is a sulfonamide derivative, and patients with documented sulfonamide hypersensitivity reactions should not receive this medication. 3, 1
• Unlike beta-blockers, brinzolamide has no pulmonary contraindications and can be safely used in patients with asthma or COPD. 5

Warnings and Precautions

Sulfonamide hypersensitivity reactions represent the primary safety concern and require immediate discontinuation if they occur. 1

Corneal edema may develop in patients with low endothelial cell counts (such as those with Fuchs' dystrophy or post-cataract surgery with endothelial compromise). 1

Avoid concomitant use of oral and topical carbonic anhydrase inhibitors due to potential additive systemic effects, though topical brinzolamide does not typically produce the acid-base disturbances or electrolyte imbalances seen with oral agents. 1, 6

Rare acid-base alterations have occurred with high-dose salicylate therapy when combined with carbonic anhydrase inhibitors. 1

Common Adverse Effects

The most frequently reported adverse effects (5–10% incidence) are:

• Blurred vision (3–8% of patients) 1, 6
• Bitter, sour, or unusual taste (metallic taste occurs in 3.7–6.8% depending on dosing frequency) 1, 2

Less common ocular effects include:

• Ocular discomfort (1.8–5.9%), which is significantly lower than dorzolamide 2% (10.7% incidence) 6, 2
• Eye pain (0.7–4.0%) 7
• Allergic dermatitis/conjunctivitis 3
• Corneal edema in susceptible patients 3
• Keratitis 3

All adverse events are generally local, transient, and mild to moderate in severity, with no serious systemic effects reported in clinical trials. 6

Clinical Efficacy

Brinzolamide 1% demonstrates IOP-lowering efficacy equivalent to dorzolamide 2% (the other topical carbonic anhydrase inhibitor) but with significantly better ocular tolerability. 6, 2

• Mean IOP reductions range from 13.2% to 21.8% depending on baseline pressure and dosing frequency. 6
• Efficacy is significantly superior to placebo but inferior to timolol 0.5% when used as monotherapy. 6
• When combined with prostaglandin analogs, brinzolamide may provide additional benefit by inhibiting the secondary increase in aqueous humor secretion that prostaglandins can induce. 7

Monitoring Requirements

IOP response should be assessed within 2–4 weeks of initiating therapy to confirm adequate pressure reduction. 5

Target IOP should be approximately 20% lower than baseline measurements, though higher reductions (25% or more) may be needed in established glaucoma with documented progression. 8, 5

Continued ophthalmologic monitoring is essential to detect disease progression through regular assessment of IOP, optic nerve structure, and visual fields. 4