TOPICAL ANTIHISTAMINES
Place IN Therapy
Place in therapy
Topical ophthalmic antihistamines function as selective histamine receptor antagonists used to decrease symptoms of itching and redness during seasonal allergic conjunctivitis. Based on three tertiary sources and 2 primary sources, topical antihistamine therapy fall first-line in place of therapy. All over-the-counter products in Canada are available in combination with decongestants. These products do not work at the source of mast cell degranulation, thus they only work to relieve symptoms rather than the underlying cause of the allergen. Due to the topical formulation, there is little systemic absorption, and low systemic adverse effects. Overall, topical antihistamines have minimal efficacy and good safety.
References
1. RxFiles OTC (Over the Counter) Products Comparative Chart. March 2012.
2) Owen C, Shah A, Smeeth L, Sheikh A. Topical treatments for seasonal allergic conjunctivitis: systemic review and meta-analysis of efficacy and effectiveness. Br J Gen Pract. 2004 June 1; 54(503): 451–456.
3) Patient Self-Care Helping Your Patients Make Therapeutic Choices, second edition. Canadian Pharmacists Association 2010.
4) Mortemousque B, Jacquet A, Richard C, et al. Randomised double masked trial comparing the efficacy and tolerance of 0.05% mequitazine eye drops versus 0.05% levocabastine and placebo in allergic conjunctivitis induced by a conjunctival provocation test with Dermatophagoides pteronyssinus. Br J Ophthalmol 2004; 88:336-40.
5) Mah F, Rosenwasser L, Townsend W. Efficacy and comfort of olopatadine 0.2% versus epinastine 0.05% ophthalmic solution for treating itching and redness induced by conjunctival allergen challenge. Curr Med Res Opin 2007; 23(6): 1445-52.