Allergic Conjunctivitis Medication

Allergic conjunctivitis can be treated with a variety of drugs. These include topical antihistamines, mast cell stabilizers, nonsteroidal anti-inflammatory drugs (NSAIDs), and corticosteroids. As always, care must be taken when using topical corticosteroids; pulsed regimen is recommended to minimize adverse reactions.

Class Summary

These agents act by competitive inhibition of histamine at the H1 receptor. They block the effects of endogenously released histamine.

Emedastine difumarate (Emadine)

This agent is a relatively selective H-receptor antagonist for topical administration. The 0.05% ophthalmic solution contains 0.884 mg/mL of emedastine difumarate.

Levocabastine

Levocabastine is a selective histamine H1 receptor antagonist. The active ingredient in this product is 0.54 mg levocabastine hydrochloride.

Epinastine (Elestat)

A direct histamine-1 receptor antagonist, epinastine does not penetrate the blood-brain barrier and therefore should not induce adverse CNS effects. It is indicated for symptoms due to allergic conjunctivitis.

Azelastine ophthalmic (Optivar)

Azelastine competes with H1-receptor sites on effector cells and inhibits release of histamine and other mediators involved in allergic response.

Bepotastine besilate ophthalmic solution (Bepreve)

Bepotastine besilate is a topically active antihistamine that directly antagonizes H1-receptors and inhibits release of histamine from mast cells. It is indicated for itching associated with allergic conjunctivitis.

Alcaftadine ophthalmic (Lastacaft)

An H1-receptor antagonist indicated for prevention of itching associated with allergic conjunctivitis, alcaftadine inhibits histamine release from mast cells, decreases chemotaxis, and inhibits eosinophil activation. It is available as a 0.25% ophthalmic solution.

Class Summary

Mast cell stabilizers inhibit the degeneration of sensitized mast cells when exposed to specific antigens by inhibiting the release of mediators from the mast cells. These agents block calcium ions from entering the mast cell. Olopatadine is a relatively selective H1 receptor antagonist and inhibitor of histamine release from mast cells.^{[6, 7]}

Lodoxamide tromethamine (Alomide)

Lodoxamide is a mast cell stabilizer. The active ingredient in this product is 1.78 mg lodoxamide tromethamine.

Olopatadine (Patanol, Pataday)

Olopatadine is a relatively selective H1 receptor antagonist and inhibitor of histamine release from mast cells. The active ingredient of Patanol is 1.11 mg olopatadine hydrochloride; Pataday is 2.22 mg olopatadine hydrochloride.

Ketotifen (Zaditor, Alaway)

Ketotifen is an over-the-counter (OTC) antihistamine eye drop. It is a noncompetitive H1-receptor antagonist and mast cell stabilizer. This agent inhibits release of mediators from cells involved in hypersensitivity reactions.

Nedocromil ophthalmic (Alocril)

Nedocromil interferes with mast cell degranulation, specifically with release of leukotrienes and platelet activating factor.

Class Summary

Corticosteroids have both anti-inflammatory (glucocorticoid) and salt retaining (mineralocorticoid) properties. Glucocorticoids have profound and varied metabolic effects. In addition, these agents modify the body's immune response to diverse stimuli.

Loteprednol etabonate (Lotemax, Alrex)

This agent decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability. It is a topical ester steroid eye drop that poses a decreased risk of glaucoma. It is available in 0.2% and 0.5% concentrations.

Class Summary

The mechanism of action of NSAIDs is believed to be through inhibition of the cyclooxygenase enzyme that is essential in the biosynthesis of prostaglandins, which results in vasoconstriction, decrease in vascular permeability and leukocytosis, and a decrease on intraocular pressure.

Ketorolac tromethamine (Acular, Acuvail)

A member of the pyrrolo-pyrrole group of NSAIDs, ketorolac inhibits prostaglandin synthesis by decreasing activity of the enzyme cyclooxygenase, which results in decreased formation of prostaglandin precursors; in turn, this results in reduced inflammation. The active ingredient is 0.5% ketorolac tromethamine.