Veterinary Medicine - August 2007 - (Page 544)

Ophthalmic medications O P E E R - R E V I E W E D veterinary medicine are 0.5% betaxolol (beta1-selective) and 0.5% timolol (nonselective). These medications may be administered every eight to 12 hours. Since beta-blockers can produce bradycardia and heart block (beta1 effects) and bronchospasm (beta2 effect), use these medications with caution in patients with cardiac or pulmonary disease. Cosopt (Merck) combines dorzolamide and timolol, which may increase ease of administration and, thus, improve owner compliance. Cosopt may be given every eight hours. Prostaglandin analogues Prostaglandin analogues, an exciting new drug class for glaucoma therapy, are highly effective ocular hypotensive agents with a rapid onset.15 Prostaglandin analogues decrease IOP by increasing outflow through the uveoscleral or unconventional outflow pathway.16 In my experience, this IOP reduction can occur within 45 to 60 minutes; thus, prostaglandin analogues may replace mannitol as the initial therapy during management of a glaucomatous crisis. The two prostaglandin analogues with proven comparable efficacy in dogs are latanoprost 0.005% (Xalatan— Pharmacia & Upjohn) and travaprost 0.004% (Travatan—Alcon) ophthalmic solutions.17 An advantage travaprost offers over latanoprost is increased stability over a wide range of temperatures. Prostaglandin analogues cause marked miosis and mild breakdown of the blood-aqueous barrier and result in a low-grade anterior uveitis, so these drugs should be used with caution in patients with secondary glaucoma due to uveitis or lens luxation. While effective in dogs and horses, prostaglandin analogues have not proved as effective in decreasing IOP in cats.15,18 Prostaglandin analogues are labeled for use in people for administration once a day; however, administration every eight to 12 hours may be required in certain cases to maintain control of the IOP. SUMMARY New pharmaceuticals for ophthalmologic problems become available every year. Veterinary ophthalmologists frequently use many of these drugs in referred cases. General practitioners may want to try these medications in their practices as well. O SUGGESTED READING Veterinary Clinics of North America: Small Animal Practice on Ocular Therapeutics edited by Cecil Moore, DVM, MS, DACVO, May 2004. REFERENCES 1. Rao A. NFATp, a cyclosporine-sensitive transcription factor implicated in cytokine gene induction. J Leukoc Biol 1995;57:536-542. 2. Kaswan RL, Salisbury MA, Ward DA. Spontaneous canine keratoconjunctivitis sicca. A useful model for human keratoconjunctivitis sicca: treatment with cyclosporine eye drops. Arch Ophthalmol 1989;107:1210-1216. 3. Berdoulay A, English RV, Nadelstein B. Effect of topical 0.02% tacrolimus aqueous suspension on tear production in dogs with keratoconjunctivitis sicca. Vet Ophthalmol 2005;8:225-232. 4. Nell B, Walde I, Billich A, et al. The effect of topical pimecrolimus on keratoconjunctivitis sicca and chronic superficial keratitis in dogs: results from an exploratory study. Vet Ophthalmol 2005;8:39-46. 5. Grahn BH, Storey ES. Lacrimostimulants and lacrimomimet- http://www.hobbsmedical.com http://www.hobbsmedical.com

Table of Contents Feed for the Digital Edition of Veterinary Medicine - August 2007

Contents A Veterinary Medicine Interview Veterinary Voices Idea Exchange Diagnosis and Treatment of Solar Dermatitis in Dogs Diagnostic Imaging for Linear Foreign Bodies in Cats Overcoming the Diagnostic and Therapeutic Challenges of Canine Immune-Mediated Thrombocytopenia Ophthalmic drugs: What’s new? CE Form Product Preview Advertiser Index Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - August 2007

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