Betaxolol Hydrochloride eent

General

• Adjust dosage to individual requirements and response of patient as determined by tonometric readings before and during therapy.1 65

• Because of diurnal variations in IOP, measure IOP at different times during the day to determine if an adequate hypotensive effect is maintained.107 Since IOP may not stabilize for a few weeks after initiating therapy, determine IOP after about 4 weeks of therapy; thereafter, determine IOP as necessary.1

Administration

Ophthalmic Administration

Apply topically to the eye as an ophthalmic solutionb or suspensiona .

Avoid contamination of the solution or suspension container.1 103 121 a b

Shake suspension well prior to use.121 122

Suspension should not be administered while wearing contact lenses.121

Dosage

Available as betaxolol hydrochloride; dosage expressed in terms of betaxolol.a

Suspension is therapeutically equivalent (in terms of magnitude and duration of hypotensive effect) to solution.121 122 126

Each 2.8 or 5.6 mg of betaxolol hydrochloride is equivalent to about 2.5 or 5 mg of betaxolol, respectively.1 2 121 a b

Adults

Betaxolol solution: 1–2 drops of a 0.5% solution in affected eye(s) twice daily. b 8 2 121 122

Betaxolol suspension: 1–2 drops of a 0.25% suspension in affected eye(s) twice daily. 1 a 8 2 121 122

If further reduction of IOP is required, a topical miotic,1 2 18 74 121 topical dipivefrin,2 12 99 122 topical epinephrine,1 12 18 74 98 121 122 and/or a carbonic anhydrase inhibitor1 2 10 12 121 122 may be added.1 2 10 12 74 121 122

Contraindications

Known hypersensitivity to betaxolol or any ingredient in the formulation.a b

Sinus bradycardia,1 18 121 a b AV block greater than first degree,1 18 121 cardiogenic shock,1 18 121 or overt cardiac failure 1 121 that is not adequately compensated (e.g., with cardiac glycosides and/or diuretics).104

Warnings/Precautions

Warnings

May be absorbed systemically following topical application to the eye; consider the usual precautions associated with systemic use of β-adrenergic blocking agents when using topical betaxolol.1 119 121 a

Severe cardiac reactions, including death associated with cardiac failure, have been reported in patients receiving topical (ocular) betaxolol.a b

Minor effects on BP 1 2 8 9 22 23 93 110 121 122 and heart rate reported.1 2 8 9 22 23 93 110

Use with caution in patients with a history of cardiac failure or heart block.1 119 121 Discontinue therapy at the first sign or symptom of cardiac failure.1 119 121

Severe respiratory reactions, including death resulting from bronchospasm, have been reported in patients with asthma receiving topical (ocular) betaxolol.1 2

Increased airway resistance and pulmonary distress (i.e., dyspnea, bronchospasm, thickened bronchial secretions, asthma, respiratory failure) reported.1 21 95 121 122 Use caution in patients with evidence of reactive airway disease on pulmonary function testing or excessive restriction of pulmonary function.1 113 121 122

Sensitivity Reactions

Possible increased reactivity to repeated accidental, diagnostic, or therapeutic challenges with a variety of allergens while taking β-adrenergic blocking agents.a b Such patients may be unresponsive to usual doses of epinephrine used to treat anaphylactic reactions.a b

General Precautions

β-Adrenergic blocking agents may mask sings and symptoms of acute hypoglycemia; administer with caution in patients subject to spontaneous hypoglycemia and in diabetic patients (especially those with labile diabetes) who are receiving hypoglycemic agents.1 88 121

β-Adrenergic blocking agents may mask signs of hyperthyroidism (e.g., tachycardia).1 121

Possible thyroid storm if β-adrenergic blocking agent is abruptly withdrawn; carefully monitor patients having or suspected of developing thyrotoxicosis.1 121

β-Adrenergic blocking agents reported to potentiate muscle weakness consistent with certain myasthenic symptoms (e.g., diplopia, ptosis, generalized weakness).1 121

Betaxolol reported rarely to increase muscle weakness in patients with myasthenia gravis or myasthenia symptoms.a b

Possible increased risks associated with general anesthesia (e.g., severe hypotension, difficulty restarting or maintaining heart beat) due to decreased ability of the heart to respond to reflex β-adrenergic stimuli.1 121 Some clinicians recommend gradual withdrawal of β-adrenergic blocking agents prior to elective surgery.1 121

Betaxolol has little to no effect on pupil size.1 2 8 9 11 12 18 93 99 121 122 Do not use alone in patients with angle-closure glaucoma; use only in combination with a miotic in these patients.1 121

Specific Populations

Category C.a b

Distributed into milk.83 Caution advised if used in nursing women.1 121

Safety and efficacy not established.1 11 121

No substantial differences in safety and efficacy relative to younger adults.a

Common Adverse Effects

Ocular stinging and discomfort on instillation.1 2 8 18 74 94 98 121 122 126

Specific Drugs

Storage

Ophthalmic

Tight containers at 15–30°C.b

Upright at 15–30°C.a

• Selective β1-adrenergic blocking agenta b 1 2 3 4 5 6 7 8 9 10 13 16 17 25 45 48 83 121 122 that does not exhibit intrinsic β1-agonist or membrane stabilizing (local anesthetic) activity.1 2 8 9 13 18 25 28 83 121 122

• One of the most potent2 6 13 16 17 25 45 48 122 and selective2 13 16 17 25 48 122 β1-adrenergic blocking agents currently available.

• Reduces both elevated1 2 8 9 11 12 14 19 93 94 121 122 and normal1 2 7 IOP8 9 10 11 14 19 93 94 121 without affecting pupillary size1 2 8 9 11 12 18 93 94 99 122 or accommodation2 8 9 11 122 and without producing miosis and/or ciliary spasm associated with miotic agents.1 2 8 9 11 12 18

• Reduces IOP by about 20–35% from baseline in patients with elevated IOP.a b 1 8 9 11 122

• Exact mechanism of action not fully elucidated; tonography and fluorophotometric studies suggest that reduced aqueous humor formation is the principal effect. a b 1 2 8 9 11 12 18 93 122

• May block endogenous catecholamine-stimulated increases in cyclic adenosine monophosphate (AMP) concentrations within the ciliary processes and subsequent formation of aqueous humor.64 65 115 116 117 118

• Does not appear to affect aqueous outflow resistance.7 19

• Tolerance may develop with prolonged use;1 however, IOP-lowering effect maintained for ≥4 years of continuous use in some patients.2 104