Understanding Glaucoma Medications (cont.)
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Beta Adrenergic Blockers
Beta adrenergic blockers, administered as eye drops, became available in the late 1970s and quickly became the most commonly used drug for the treatment of glaucoma. Since the advent of the prostaglandin group of drugs, beta adrenergic locking drops have become the second most widely used therapy. This group includes timolol (Timoptic Betimol, Istalol), levobunolol (Betagan, AKBeta), betaxolol (Betoptic), carteolol (Ocupress), and metipranolol (OptiPranolol). Timolol is currently available in a generic form.
How beta blockers work: These drugs lower intraocular pressure by reducing the amount of aqueous humor produced.
Most adrenergic beta blockers are nonselective and block both the beta-1 and beta-2 receptors. A nonselective blocker inhibits both heart muscle and opening of the airways of the lungs. These are, therefore, contraindicated in patients with asthma, emphysema, chronic obstructive pulmonary disease (COPD), bradycardia (low pulse rate), and congestive heart failure. Betaxolol (Betoptic) is a selective beta-1 receptor antagonist. Its mechanism of action is similar to timolol, but since it is a selective beta-1 blocker, it is better tolerated in patients with lung disease than timolol.
Who should not use these medications:
Use: These drugs are administered as eye drops to the affected eye(s).
Drug or food interactions: Ocular beta blockers may have additive effects when used with oral beta blockers. Additive effects occur when used with other drugs that lower intraocular pressure.
Side effects: Beta blockers may contain sulfites, which may cause allergic-type reactions. Rarely, use may worsen or cause symptoms similarly observed with orally administered beta blockers, such as heart disturbances (abnormal heart rhythm, heart attack, or heart failure), asthma, chronic obstructive pulmonary disease, impotence, or mental changes (especially in elderly persons).
Medically Reviewed by a Doctor on 11/21/2012
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While any type of glaucoma can be unilateral, primary open-angle glaucoma, primary angle-closure glaucoma, primary infantile glaucoma, juvenile-onset glaucoma, and pigmentary glaucoma are generally bilateral diseases, the severity of which may be asymmetric in the two eyes.