No

Carbonic Anhydrase Inhibitor; Ophthalmic Agent, Antiglaucoma

Lowers intraocular pressure to treat glaucoma in patients with ocular hypertension or open-angle glaucoma

C

Hypersensitivity to any component of the product; contains benzalkonium chloride as a preservative

Although administered topically, systemic absorption occurs. Same types of adverse reactions attributed to sulfonamides may occur with topical administration.

Because dorzolamide and its metabolite are excreted predominantly by the kidney, it is not recommended for use in patients with severe renal impairment (Cl_cr <30 mL/minute); use with caution in patients with hepatic impairment

Local ocular adverse effects (conjunctivitis and lid reactions) were reported with chronic administration. Many resolved with discontinuation of drug therapy. If such reactions occur, discontinue dorzolamide.

There is a potential for an additive effect in patients receiving an oral carbonic anhydrase inhibitor and dorzolamide. The concomitant administration of dorzolamide and oral carbonic anhydrase inhibitors is not recommended.

Benzalkonium chloride is the preservative in dorzolamide which may be absorbed by soft contact lenses. Dorzolamide should not be administered while wearing soft contact lenses.

>10%:

Gastrointestinal: Bitter taste following administration (25%)

Ocular: Burning, stinging or discomfort immediately following administration (33%); superficial punctate keratitis (10% to 15%); signs and symptoms of ocular allergic reaction (10%)

5% to 10% Ocular: Blurred vision, tearing, dryness, photophobia

<1%: Headache, fatigue, rashes, nausea, urolithiasis, weakness, iridocyclitis, xerostomia

Symptoms of overdose include electrolyte imbalance, development of an acidotic state and possible CNS effects

Treatment is symptomatic

Increased toxicity: Salicylates use may result in carbonic anhydrase inhibitor accumulation and toxicity including CNS depression and metabolic acidosis

Store at room temperature (25°C)

Reversible inhibition of the enzyme carbonic anhydrase resulting in reduction of hydrogen ion secretion at renal tubule and an increased renal excretion of sodium, potassium, bicarbonate, and water to decrease production of aqueous humor; also inhibits carbonic anhydrase in central nervous system to retard abnormal and excessive discharge from CNS neurons

Peak effect: 2 hours

Duration: 8-12 hours

Absorption: Topical: Reaches the systemic circulation where it accumulates in RBCs during chronic dosing as a result of binding to CA-11

Distribution: Accumulates in RBCs during chronic administration

Protein binding: 33%

Half-life: Terminal RBC half-life of 147 days

Metabolism: Metabolized to N-desethyl metabolite that also inhibits carbonic anhydrase less potently than the parent drug

Elimination: Dorzolamide and its metabolite (N-desethyl) are excreted in the urine. After dosing is stopped, dorzolamide washes out of RBCs nonlinearly, resulting in a rapid decline of drug concentration initially, followed by a slower elimination phase with a half-life of about 4 months.

Adults: Glaucoma: Instill 1 drop in the affected eye(s) 3 times/day

If more than one topical ophthalmic drug is being used, administer the drugs at least 10 minutes apart

Instruct patients to avoid allowing the tip of the dispensing container to contact the eye or surrounding structures. Ocular solutions can become contaminated by common bacteria known to cause ocular infections. Serious damage to the eye and subsequent loss of vision may occur from using contaminated solutions.

Monitor serum electrolyte levels (potassium) and blood pH levels; Ophthalmic exams and IOP periodically

May cause drowsiness

None reported

No information available to require special precautions

No effects or complications reported

If serious or unusual reactions or signs of hypersensitivity occur, discontinue use of the product

If any ocular reactions, particularly conjunctivitis and lid reactions, discontinue use and seek physician's advice. If an intercurrent ocular condition (eg, trauma, ocular surgery, infection) occur, immediately seek your physician's advice concerning the continued use of the present multidose container.

Avoid allowing the tip of the dispensing container to contact the eye or surround structures

Solution, ophthalmic, as hydrochloride: 2%

Biollaz J, Munafo A, Buclin T, et al, "Whole Blood Pharmacokinetics and Metabolic Affects of the Topical Carbonic Anhydrase Inhibitor Dorzolamide," Eur J Clin Pharmacol, 1995, 47(5):455-60.

Wilkerson M, Cyrlin M, Lippa EA, et al, "Four-Week Safety and Efficacy Study of Dorzolamide, a Novel, Active, Topical Carbonic Anhydrase Inhibitor," Arch Ophthalmol, 1993, 111(10):1343-50.