Ocular Hypertension and Glaucoma
In ophthalmology, topical betaxolol hydrochloride is used to reduce elevated IOP in various conditions, including chronic open-angle glaucoma and ocular hypertension. 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. Controlled studies of betaxolol 0.25% resin-formulated suspension versus the 0.5% solution in patients with primary open-angle glaucoma or ocular hypertension have demonstrated that the resin-formulated suspension is therapeutically equivalent (i.e., in terms of the magnitude and duration of the hypotensive effect) to the solution.
Betaxolol may be used alone or in conjunction with a topical miotic (e.g., pilocarpine), topical dipivefrin, topical epinephrine, and/or a carbonic anhydrase inhibitor. When used in conjunction with these agents, betaxolol may have an additive IOP-lowering effect. Because betaxolol has little or no effect on pupil size, a miotic should be used concomitantly in patients with angle-closure glaucoma.
Like timolol, betaxolol reduces elevated IOP in patients with chronic open-angle glaucoma without producing the miosis and/or ciliary spasm that are associated with miotic agents. In addition, use of betaxolol in patients with central lenticular opacities can avoid the visual impairment caused by a constricted pupil. Usual dosages of betaxolol appear to be as effective as usual dosages of timolol in reducing IOP in patients with chronic open-angle glaucoma; however, unlike timolol, betaxolol has been associated with minimal adverse pulmonary or cardiovascular effects. Several studies involving small numbers of patients indicate that topical betaxolol may be used safely in some patients with chronic open-angle glaucoma who have coexisting reactive airway disease (e.g., asthma, chronic bronchitis, chronic obstructive pulmonary disease), including some who cannot tolerate nonselective β-blocking agents (e.g., timolol) or in whom these nonselective agents are contraindicated; however, increased airway resistance and pulmonary distress have been reported following topical application of betaxolol to the eye and the drug should be used with caution in patients with evidence of reactive airway disease on pulmonary function testing or excessive restriction of pulmonary function.
(See Cautions: Systemic Effects.)
During prolonged therapy with topical betaxolol, the effect in reducing IOP is generally well maintained, but tolerance has been reported in some patients. The reduction in mean IOP has been maintained for up to 4 years after initial stabilization with the drug in some patients. Betaxolol has been used effectively and has been well tolerated in some patients with glaucoma who have undergone laser trabeculoplasty and have needed additional long-term ocular hypotensive therapy; in some aphakic patients; and in patients with glaucoma who wear hard or soft contact lenses.
For systemic uses of betaxolol hydrochloride, see 24:24.