Travoprost, an isopropyl ester prodrug, is a synthetic prostaglandin F2 alpha analogue that is rapidly hydrolyzed by esterases in the cornea to its biologically active free acid. The travoporst free acid is potent and highly selective for the FP prostanoid receptor. Travoprost free acid is a selective FP prostanoid receptor agonist and is believed to reduce intraocular pressure by increasing the drainage of aqueous humor, which is done primarily through increased uveoscleral outflow and to a lesser extent, trabecular outflow facility. Travoprost ophthalmic solution is used for the reduction of elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension who are intolerant of other intraocular pressure lowering medications or insufficiently responsive (failed to achieve target IOP determined after multiple measurements over time) to another intraocular pressure lowering medication. Travoprost is known by the brand names of Travatan and Travatan Z, manufactured by Alcon.

Brinzolamide reduces the amount of fluid in the eye, which decreases pressure inside the eye. Brinzolamide is a carbonic anhydrase inhibitor that is FDA approved for the treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma. Common adverse reactions include abnormal taste in mouth and blurred vision. The concomitant administration of brinzolamide and oral carbonic anhydrase inhibitors is not recommended. Plus, in patients treated with oral carbonic anhydrase inhibitors, rare instances of acid-base alterations have occurred with high-dose salicylate therapy.

Cidofovir is an antiviral nucleotide analogue with significant activity against cytomegalovirus (CMV) and other herpesviruses. Cidofovir suppresses cytomegalovirus (CMV) replication by selective inhibition of viral DNA synthesis. Biochemical data support selective inhibition of CMV DNA polymerase by cidofovir diphosphate, the active intracellular metabolite of cidofovir. Incorporation of cidofovir into the growing viral DNA chain results in reductions in the rate of viral DNA synthesis. Cidofovir is indicated for the treatment of CMV retinitis in patients with acquired immunodeficiency syndrome.

Olopatadine is an antihistamine (as well as anticholinergic and mast cell stabilizer) used to treat itching associated with allergic conjunctivitis (eye allergies). Olopatadine is a selective histamine H1 antagonist that binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine. Olopatadine is devoid of effects on alpha-adrenergic, dopamine and muscarinic type 1 and 2 receptors. Some known side effects include a headache (7% of occurrence), eye burning and/or stinging (5%), blurred vision, dry eyes, foreign body sensation, hyperemia, keratitis, eyelid edema, pruritus, asthenia, sore throat (pharyngitis), rhinitis, sinusitis, and taste perversion.

Brimonidine reduces the amount of fluid in the eye, which decreases pressure inside the eye. Brimonidine ophthalmic (for the eyes) is used to treat open-angle glaucoma or ocular hypertension (high pressure inside the eye). Brimonidine is an alpha adrenergic receptor agonist (primarily alpha-2). Fluorophotometric studies in animals and humans suggest that Brimonidine has a dual mechanism of action by reducing aqueous humor production and increasing uveoscleral outflow. Adverse reactions occurring in approximately 10­20% of the subjects receiving brimonidine ophthalmic solution (0.1-0.2%) included: allergic conjunctivitis, conjunctival hyperemia, and eye pruritus. Because Brimonidine may reduce blood pressure, caution in using drugs such as antihypertensives and/or cardiac glycosides with Brimonidine is advised.

Timolol is the non-selective Beta antagonist used as eye drops to treat increased pressure inside the eye such as in ocular hypertension and glaucoma. Timolol is also used for high blood pressure, chest pain due to insufficient blood flow to the heart, to prevent further complications after a heart attack, and to prevent migraines. Timolol is a beta1 and beta2 (non-selective) adrenergic receptor antagonist that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anesthetic (membrane-stabilizing) activity. Timolol, when applied topically on the eye, has the action of reducing elevated, as well as normal intraocular pressure, whether or not accompanied by glaucoma. Elevated intraocular pressure is a major risk factor in the pathogenesis of glaucomatous visual field loss and optic nerve damage. The precise mechanism of the ocular hypotensive action of Timolol is not clearly established at this time. Tonography and fluorophotometry studies of the timolol maleate ophthalmic solution in man suggest that its predominant action may be related to the reduced aqueous formation. However, in some studies, a slight increase in outflow facility was also observed. In a study of plasma drug concentration in six subjects, the systemic exposure to timolol was determined following once daily administration of Timolol Maleate Ophthalmic Gel Forming Solution 0.5% in the morning. The mean peak plasma concentration following this morning dose was 0.28 ng/mL. Side effects, when given in the eye, include burning sensation, eye redness, superficial punctate keratopathy, corneal numbness.

Emedastine is an antihistaminic agent, which was approved by FDA for the treatment of allergic conjunctivitis (Emadine brand name). The drug acts selectively on H1 receptors with lower affinity to H2 and H3 subtypes. Emedastine has a relatively unfavorable CNS effect profile. A small percentage of patients reported somnolence as an adverse effect after administration.

Pegaptanib is a selective vascular endothelial growth factor (VEGF) antagonist indicated for the treatment of neovascular (wet) age-related macular degeneration. Pegaptanib is an aptamer, a pegylated modified single-stranded oligonucleotide, which adopts a threedimensional conformation that enables it to bind to extracellular VEGF. Pegaptanib specifically binds to the 165 isoform of VEGF, a protein that plays a critical role in angiogenesis (the formation of new blood vessels) and increased permeability (leakage from blood vessels), two of the primary pathological processes responsible for the vision loss associated with neovascular age-related macular degeneration. Pegaptanib is administered in a 0.3 mg dose once every six weeks by intravitreal injection. An intravitreal injection is one that is administered directly into the eye, more specifically, into the vitreous humour, or the jelly-like fluid within the eye.