Unoprostone Isopropyl is a synthetic docosanoid and a structural analogue of an inactive biosynthetic cyclic derivative of arachidonic acid, 13,14-dihydro-15-keto-prostaglandin F 2a. Although the mechanism of action is unknown, unoprostone isopropyl is believed to reduce elevated intraocular pressure by increasing the outflow of aqueous humor through the trabecular meshwork. Unoprostone isopropyl (UI) may have a local effect on Big Potassium channels and ClC-2 chloride channels, but the exact mechanism is unknown at this time. Unoprostone is used for the management of open-angle glaucoma and ocular hypertension. The therapeutic efficacy of Unoprostone can be decreased when used in combination with Celecoxib, Diclofenac, Diflunisal, Etodolac and some other drugs. Unoprostone isopropyl ophthalmic solution may gradually increase the pigmentation of the iris, cause pigment changes (darkening) to periorbital pigmented tissues and eyelashes, exacerbate active intraocular inflammation (e.g., uveitis), and cause macular edema. In clinical studies, the most common ocular adverse reactions with use of Rescula were burning/stinging, burning/stinging upon drug instillation, dry eyes, itching, increased length of eyelashes, and injection. These were reported in approximately 10–25% of patients. Ocular adverse reactions occurring in approximately 5–10% of patients were abnormal vision, eyelid disorder, foreign body sensation, and lacrimation disorder. Other adverse reactions occurred more rarely.

Dipivefrin is a prodrug with little or no pharmacologically activity until it is hydrolyzed into epinephrine inside the human eye. The liberated epinephrine, an adrenergic agonist, appears to exert its action by stimulating α -and/or β2-adrenergic receptors, leading to a decrease in aqueous production and an enhancement of outflow facility. The dipivefrin prodrug delivery system is a more efficient way of delivering the therapeutic effects of epinephrine, with fewer side effects than are associated with conventional epinephrine therapy. Dipivefrin is used as initial therapy for the control of intraocular pressure in chronic open-angle glaucoma.

Demecarium (HUMORSOL®) is an indirect-acting parasympathomimetic agent, also known as a cholinesterase inhibitor and anticholinesterase. Cholinesterase inhibitors prolong the effect of acetylcholine, which is released at the neuroeffector junction of parasympathetic postganglion nerves, by inactivating the cholinesterases that break it down. Application of demecarium (HUMORSOL®) to the eye produces intense miosis and ciliary muscle contraction due to inhibition of cholinesterase, allowing acetylcholine to accumulate at sites of cholinergic transmission. These effects are accompanied by increased capillary permeability of the ciliary body and iris, increased permeability of the blood-aqueous barrier, and vasodilation. Myopia may be induced or, if present, may be augmented by the increased refractive power of the lens that results from the accommodative effect of the drug. Demecarium (HUMORSOL®) indirectly produces some of the muscarinic and nicotinic effects of acetylcholine as quantities of the latter accumulate.

Homatropine (used in a form of bromide or methylbromide salts) is an analogue of atropine, which acts as an antagonist of muscarinic receptors. Homatropine was approved for the treatment of cough in combination with hydrocodone bitartrate.

Diquafosol, a dinucleotide Up4U, is an agonist for purinergic P2Y2 receptor. Diquafosol stimulated water and mucin secretion by acting on P2Y2 receptors on the conjunctival epithelial and goblet cell membrane and elevating intracellular calcium ion concentrations. The Japanese Ministry of Health, Labour and Welfare granted approval for DIQUAS Ophthalmic Solution 3% (diquafosol tetrasodium) for the treatment of dry eye.