Medication Summary
The goals of pharmacotherapy are to reduce morbidity and to prevent complications.
Carbonic anhydrase inhibitors
Class Summary
Carbonic anhydrase is an enzyme found in many tissues of the body, including the eye. Catalyzes a reversible reaction where carbon dioxide becomes hydrated and carbonic acid becomes dehydrated. By slowing the formation of bicarbonate ions with subsequent reduction in sodium and fluid transport, it may inhibit carbonic anhydrase in the ciliary processes of the eye. This effect decreases aqueous humor secretion, reducing IOP.
Acetazolamide (Diamox Sequels)
Inhibits enzyme carbonic anhydrase, reducing the rate of aqueous humor formation, which, in turn, reduces IOP.
Dorzolamide (Trusopt)
Used concomitantly with other topical ophthalmic drug products to lower IOP. If more than one ophthalmic drug is being used, administer the drugs at least 10 min apart. Reversibly inhibits carbonic anhydrase, reducing hydrogen ion secretion at renal tubule and increasing renal excretion of sodium, potassium bicarbonate, and water to decrease production of aqueous humor.
Alpha-adrenergic agonists
Class Summary
Decrease IOP, possibly by reducing aqueous humor production.
Apraclonidine (Iopidine)
Reduces elevated and normal IOP whether or not accompanied by glaucoma. Apraclonidine is a relatively selective alpha-adrenergic agonist that does not have significant local anesthetic activity. Has minimal cardiovascular effects.
Hyperosmotic agents
Class Summary
Lower IOP by creating an osmotic gradient between ocular fluids and plasma. They are not for long-term use.
Mannitol (Osmitrol)
Reduces elevated IOP when the pressure cannot be lowered by other means. Initially assess for adequate renal function in adults by administering a test dose of 200 mg/kg, given IV over 3-5 min. Should produce a urine flow of at least 30-50 mL/h over 2-3 h. In children, assess for adequate renal function by administering a test dose of 200 mg/kg, given IV over 3-5 min. Should produce a urine flow of at least 1 mL/h over 1-3 h.
Prostaglandins, Ophthalmic
Class Summary
Decrease IOP, possibly by increasing uveoscleral outflow of aqueous humor.
Bimatoprost ophthalmic solution (Lumigan, Latisse)
Prostaglandin agonist that selectively mimics effects of naturally occurring substances, prostamides. Exact mechanism of action unknown but believed to reduce IOP by increasing outflow of aqueous humor through trabecular meshwork and uveoscleral routes.
Travoprost ophthalmic solution (Travatan Z)
Prostaglandin F2-alpha analog and selective FP prostanoid receptor agonist. Exact mechanism of action unknown but believed to reduce IOP by increasing uveoscleral outflow.
Latanoprost (Xalatan, Xelpros)
May decrease IOP by increasing outflow of aqueous humor.
Antiglaucoma, Beta-Blockers
Class Summary
These agents decrease aqueous production, possibly by blocking adrenergic beta receptors present in the ciliary body. The nonselective medications in this class also interact with the beta receptors in the heart and lungs, causing significant adverse effects.
Levobunolol (AKBeta, Betagan)
Nonselective beta-adrenergic blocking agent that lowers IOP by reducing aqueous humor production.
Timolol ophthalmic (Istalol, Betimol, Timoptic, Timoptic-XE)
May reduce elevated and normal IOP, with or without glaucoma, by reducing production of aqueous humor or by outflow.
Antiglaucoma, Combination Agents
Class Summary
A combination solution that can decrease aqueous humor secretion more than would each solution used as monotherapy, while improving compliance.
Brimonidine/timolol (Combigan)
Selective alpha-2 adrenergic receptor agonist with a nonselective beta-adrenergic receptor inhibitor. Each of them decrease elevated IOP, whether or not associated with glaucoma damage.
Brinzolamide/ and brimonidine (Simbrinza)
Brinzolamide catalyzes reversible reaction involving hydration of carbon dioxide and dehydration of carbonic acid. May use concomitantly with other topical ophthalmic drug products to lower IOP. If more than 1 topical ophthalmic drug is being used, administer drugs at least 10 min apart.
Brimonidine is a relatively selective alpha2 adrenergic-receptor agonist that decreases IOP by dual mechanisms, reducing aqueous humor production and increasing uveoscleral outflow. Brimonidine has minimal effect on cardiovascular and pulmonary parameters. A moderate risk of allergic response to this drug exists. Caution should be used in individuals who have developed an allergy to Iopidine.
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Phacomorphic glaucoma.
