Carbonic anhydrase inhibitors Ophthalmology

• Brinzolamide ophthalmic suspension 1% (Azopt®
• Dorzolamide HCI 2% (Trusopt®)

 

Carbonic anhydrase inhibitors (decrease inflow)

 

Overview

1. Efficacy of brinzolamide 1% ~ equivalent to that of dorzolamide 2%.
2. chemically related to sulfonamide antibiotics
3. Administered two or three times daily.
4. Effects on blood pressure or heart rate were minimal.
5. approximately one third of patients treated with dorzolamide 2% experienced some level of ocular burn, sting, or discomfort. burning was less frequent with brinzolamide 1%.
6. They lower IOP by inhibiting aqueous secretion and via the topical route are used three times daily as monotherapy or twice daily as adjunctive treatment.
7. e overall allergic rate was approximately 10%. In general, dorzolamide and brinzolamide are well tolerated.
8. The use of dorzolamide in children was reviewed retrospectively in one study; no significant health problems were identified with acute or chronic use of this drug
9. Slightly less effective than beta-blockers but may have a supplementary neuroprotective effect
10. CAI are relatively contraindicated in patients allergic to sulfonamide antibiotics

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Brinzolamide ophthalmic suspension 1% (Azopt®)

 

Brinzolamide ophthalmic suspension 1% (Azopt®) 

Pharmacology:   AZOPT® (brinzolamide ophthalmic suspension) 1% contains brinzolamide, an inhibitor of carbonic anhydrase II (CA-II). Following topical ocular administration, brinzolamide inhibits aqueous humor formation and reduces elevated intraocular pressure.

Dosing: Instill one drop in the affected eye(s) three times daily.

Side effects: Most common adverse reactions are blurred vision and bitter, sour or unusual taste.

Efficacy: In two, three-month clinical studies, AZOPT® (brinzolamide ophthalmic suspension) 1% dosed three times per day in patients with elevated intraocular pressure (IOP), produced significant reductions in IOPs (4 to 5 mmHg). These IOP reductions are equivalent to the reductions observed with TRUSOPT* (dorzolamide hydrochloride ophthalmic solution) 2% dosed three times per day in the same studies.

In two clinical studies in patients with elevated intraocular pressure, AZOPT® (brinzolamide ophthalmic suspension) 1% was associated with less stinging and burning upon instillation than TRUSOPT* 2%.

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Dorzolamide HCI 2% (Trusopt®)

 

Dorzolamide HCI 2% (Trusopt®) 

 

Pharmacology:   Carbonic anhydrase (CA) is an enzyme found in many tissues of the body including the eye. It catalyzes the reversible reaction involving the hydration of carbon dioxide and the dehydration of carbonic acid. In humans, carbonic anhydrase exists as a number of isoenzymes, the most active being carbonic anhydrase II (CA-II), found primarily in red blood cells (RBCs), but also in other tissues. 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. The result is a reduction in intraocular pressure (IOP).

Dorzolamide HCl Ophthalmic Solution contains dorzolamide hydrochloride, an inhibitor of human carbonic anhydrase II. Following topical ocular administration, Dorzolamide HCl Ophthalmic Solution reduces elevated intraocular pressure.

Dosing: The dose is one drop of Dorzolamide HCl Ophthalmic Solution in the affected eye(s) three times daily. Dorzolamide HCl Ophthalmic Solution may be used concomitantly with other topical ophthalmic drug products to lower intraocular pressure.

Side effects: The most frequently reported adverse reactions associated with Dorzolamide HCl Ophthalmic Solution were ocular burning, stinging, or discomfort immediately following ocular administration (approximately one-third of patients). Approximately one-quarter of patients noted a bitter taste following administration. Superficial punctate keratitis occurred in 10 to 15% of patients and signs and symptoms of ocular allergic reaction in approximately 10%

Efficacy: The efficacy of Dorzolamide HCl Ophthalmic Solution was demonstrated in clinical studies in the treatment of elevated intraocular pressure in patients with glaucoma or ocular hypertension (baseline IOP >/= 23 mmHg). The IOP-lowering effect of Dorzolamide HCl Ophthalmic Solution was approximately 3 to 5 mmHg throughout the day and this was consistent in clinical studies of up to one year duration.

The efficacy of Dorzolamide HCl Ophthalmic Solution when dosed less frequently than three times a day (alone or in combination with other products) has not been established.

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Oral:

Acetazolamide (Diamox® Sequels®)
Methazolamide (Neptazane®)