Abstract

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The effects of oral cyclosporine on tear production in dogs with keratoconjunctivitis sicca (KCS) were evaluated in 20 KCS-affected dogs. Dogs were given a full ophthalmic examination with bilateral Schirmer tear test (STT) readings taken together with evaluation of blepharospasm, conjunctival hyperaemia, ocular discharge, corneal opacification, vascularisation and pigmentation scored between 0 (none) and 4 (severe), these summated to give a total clinical score. Dogs were treated with topical carbomer gel (Viscotears: Novartis Ophthalmics) three times daily and oral cyclosporine (Atopica: Novartis) 5mg/kg once daily for the first 42 days, then every other day for the next 28 days then twice weekly to the end of the study. Dogs were removed from the trial if ocular surface pathology did not improve or deteriorated or if gastrointestinal side effects were marked. STT rose from 5.7±2.3mm/min to 10.7±5.9mm/min (p< 0.0001) with daily cyclosporine administration falling to 8.7±6.0mm/min (p=0.017) on twice weekly administration. Total clinical score fell from 8.0±3.3 to 4.6±3.0 (p=0.0019) with daily cyclosporine administration rising to 5.6±3.9 (p=0.0014) on twice weekly administration. Two dogs were withdrawn for reasons of inefficacy during the study, one with poor owner compliance, one because of drug side effects of vomiting and diarrhoea while two dogs died of unrelated causes during the study. These results show that cyclosporine given per os has a lacrimogenic action which may be useful in dogs where topical application is difficult.

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