Apraclonidine

INDICATIONS AND USAGE Apraclonidine ophthalmic solution 0.5% is indicated for short-term adjunctive therapy, in patients on maximally tolerated medical therapy, who require additional IOP reduction. Patients on maximally tolerated medical therapy, who are treated with apraclonidine ophthalmic solution 0.5% to delay surgery, should have frequent follow-up examinations and treatment should be discontinued if the IOP rises significantly. The addition of apraclonidine ophthalmic solution 0.5% to patients already using two aqueous suppressing drugs (i.e., beta-blocker plus carbonic anhydrase inhibitor) as part of their maximally tolerated medical therapy may not provide additional benefit. This is because apraclonidine ophthalmic solution 0.5% is an aqueous suppressing drug and the addition of a third aqueous suppressant may not significantly reduce IOP. The IOP lowering efficacy of apraclonidine ophthalmic solution 0.5% diminishes over time in some patients. This loss of effect, or tachyphylaxis, appears to be an individual occurrence with a variable time of onset and should be closely monitored. The benefit for most patients is less than one month.

DOSAGE AND ADMINISTRATION One to two drops of apraclonidine ophthalmic solution 0.5% should be instilled in the affected eye(s) three times daily. Since apraclonidine ophthalmic solution 0.5% will be used with other ocular glaucoma therapies, an approximate 5 minute interval between instillation of each medication should be practiced to prevent washout of the previous dose. NOT FOR INJECTION INTO THE EYE. NOT FOR ORAL INGESTION.

WARNINGS FOR TOPICAL OPHTHALMIC USE ONLY. Not for injection or oral ingestion. Topical administration of apraclonidine have been reported to cause cardiovascular collapse requiring intubation and ventilation in pediatric patients 6 years and younger, including neonates. Systemic adverse reactions such as prolonged lethargy and unresponsiveness, apnea, hypoxia, respiratory failure, bradycardia, hypertension, hypotension, hypothermia, hypotonia, pallor have also been reported. Appropriate monitoring in a clinical setting should be in place.

CONTRAINDICATIONS Apraclonidine ophthalmic solution 0.5% is contraindicated in patients with hypersensitivity to apraclonidine or any other component of this medication, as well as systemic clonidine. It is also contraindicated in patients receiving monoamine oxidase (MAO) inhibitors.

Drug Interactions Apraclonidine should not be used in patients receiving MAO inhibitors (see CONTRAINDICATIONS). Although no specific drug interactions with topical glaucoma drugs or systemic medications were identified in clinical studies of apraclonidine ophthalmic solution 0.5%, the possibility of an additive or potentiating effect with CNS depressants (alcohol, barbiturates, opiates, sedatives, anesthetics) should be considered. Tricyclic antidepressants have been reported to blunt the hypotensive effect of systemic clonidine. It is not known whether the concurrent use of these agents with apraclonidine can lead to a reduction in IOP lowering effect. No data on the level of circulating catecholamines after apraclonidine withdrawal are available. Caution, however, is advised in patients taking tricyclic antidepressants which can affect the metabolism and uptake of circulating amines. An additive hypotensive effect has been reported with the combination of systemic clonidine and neuroleptic therapy. Systemic clonidine may inhibit the production of catecholamines in response to insulin-induced hypoglycemia and mask the signs and symptoms of hypoglycemia. Since apraclonidine may reduce pulse and blood pressure, caution in using drugs such as beta-blockers (ophthalmic and systemic), antihypertensives, and cardiac glycosides is advised. Patients using cardiovascular drugs concurrently with apraclonidine ophthalmic solution 0.5% should have pulse and blood pressures frequently monitored. Caution should be exercised with simultaneous use of clonidine and other similar pharmacologic agents.

ADVERSE REACTIONS In clinical studies the overall discontinuation rate related to apraclonidine ophthalmic solution 0.5% was 15%. The most commonly reported events leading to discontinuation included (in decreasing order of frequency) hyperemia, pruritus, tearing, discomfort, lid edema, dry mouth, and foreign body sensation. The following adverse reactions (incidences) were reported in clinical studies of apraclonidine ophthalmic solution 0.5% as being possibly, probably, or definitely related to therapy: Ocular The following adverse reactions were reported in 5% to 15% of the patients: discomfort, hyperemia, and pruritus. The following adverse reactions were reported in 1% to 5% of the patients: blanching, blurred vision, conjunctivitis, discharge, dry eye, foreign body sensation, lid edema, and tearing. The following adverse reactions were reported in less than 1% of the patients: abnormal vision, blepharitis, blepharoconjunctivitis, conjunctival edema, conjunctival follicles, corneal erosion, corneal infiltrate, corneal staining, edema, irritation, keratitis, keratopathy, lid disorder, lid erythema, lid margin crusting, lid retraction, lid scales, pain, and photophobia. Nonocular Dry mouth occurred in approximately 10% of the patients. The following adverse reactions were reported in less than 3% of the patients: abnormal coordination, asthenia, arrhythmia, asthma, chest pain, constipation, contact dermatitis, depression, dermatitis, dizziness, dry nose, dyspnea, facial edema, headache, insomnia, malaise, myalgia, nausea, nervousness, paresthesia, parosmia, peripheral edema, pharyngitis, rhinitis, somnolence, and taste perversion. Clinical Practice The following events have been identified during postmarketing use of apraclonidine ophthalmic solution 0.5% in clinical practice. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. The events, which have been chosen for inclusion due to either their seriousness, frequency of reporting, possible causal connection to apraclonidine ophthalmic solution 0.5%, or a combination of these factors, include bradycardia and hypersensitivity.

CLINICAL PHARMACOLOGY Apraclonidine hydrochloride is a relatively selective alpha-2-adrenergic agonist. When instilled in the eye, apraclonidine ophthalmic solution 0.5%, has the action of reducing elevated, as well as normal, intraocular pressure (IOP), whether or not accompanied by glaucoma. Ophthalmic apraclonidine has minimal effect on cardiovascular parameters. Elevated IOP presents a major risk factor in glaucomatous field loss. The higher the level of IOP, the greater the likelihood of optic nerve damage and visual field loss. Apraclonidine ophthalmic solution 0.5% has the action of reducing IOP. The onset of action of apraclonidine can usually be noted within one hour, and maximum IOP reduction occurs about three hours after instillation. Aqueous fluorophotometry studies demonstrate that apraclonidine's predominant mechanism of action is reduction of aqueous flow via stimulation of the alpha-adrenergic system. Repeated dose-response and comparative studies (0.125%-1.0% apraclonidine) demonstrate that 0.5% apraclonidine is at the top of the dose-response IOP reduction curve. The clinical utility of apraclonidine ophthalmic solution 0.5% is most apparent for those glaucoma patients on maximally tolerated medical therapy. Patients on maximally tolerated medical therapy with uncontrolled IOP, and scheduled to undergo laser trabeculoplasty or trabeculectomy surgery were enrolled into a double-masked, placebo-controlled, multicenter clinical trial to determine if apraclonidine ophthalmic solution 0.5%, dosed three times daily, could delay the need for surgery for up to three months. All patients enrolled into this trial had advanced glaucoma and were undergoing maximally tolerated medical therapy, i.e., patients were using combinations of a topical beta blocker, sympathomimetics, parasympathomimetics and oral carbonic anhydrase inhibitors. Patients were considered to be treatment failures in this study if, in the opinion of the investigators, their IOP was uncontrolled by the masked study medication or there was evidence of further optic nerve damage or visual field loss, and surgery was indicated. Of 171 patients receiving masked medication, 84 were treated with apraclonidine ophthalmic solution 0.5% and 87 were treated with placebo (apraclonidine vehicle). Apraclonidine treatment resulted in a significantly greater percentage of treatment successes compared to patients treated with placebo. In this placebo-controlled maximum therapy trial, 14.3% of patients treated with apraclonidine ophthalmic solution 0.5% were discontinued due to adverse events, primarily allergic-like reactions (12.9%). The IOP lowering efficacy of apraclonidine ophthalmic solution 0.5% diminishes over time in some patients. This loss of effect, or tachyphylaxis, appears to be an individual occurrence with a variable time of onset and should be closely monitored. An unpredictable decrease of IOP control in some patients, incidence of ocular allergic responses and systemic side effects, may limit the utility of apraclonidine ophthalmic solution 0.5%. However, patients on maximally tolerated medical therapy may still benefit from the additional IOP reduction provided by the short-term use of apraclonidine ophthalmic solution 0.5%. Topical use of apraclonidine ophthalmic solution 0.5% leads to systemic absorption. Studies of apraclonidine ophthalmic solution 0.5% dosed one drop three times a day in both eyes for 10 days, in normal volunteers, yielded mean peak and trough concentrations of 0.9 ng/mL and 0.5 ng/mL, respectively. The half-life of apraclonidine ophthalmic solution 0.5% was calculated to be 8 hours. Apraclonidine ophthalmic solution 0.5%, because of its alpha adrenergic activity, is a vasoconstrictor. Single dose ocular blood flow studies in monkeys, using the microsphere technique, demonstrated a reduced blood flow for the anterior segment; however, no reduction in blood flow was observed in the posterior segment of the eye after a topical dose of apraclonidine ophthalmic solution 0.5%. Ocular blood flow studies have not been conducted in humans.