Keratoconjunctivitis sicca exacerbation in a dog treated with systemic atenolol

A 6-year-old, intact, male English cocker spaniel was referred for treatment of chronic conjunctivitis and unilateral keratitis. The dog was diagnosed with bilateral immune-mediated keratoconjunctivitis sicca, treated with topical cyclosporine 0·2% ointment and sodium hyaluronate eye drops and improved considerably. After 2 months, pulmonic stenosis was diagnosed, and the dog commenced treatment with oral atenolol; theophthalmological disease worsened dramatically within a few days. The ophthalmic signs rapidly improved after discontinuation of atenolol, and there was bilateral complete remission after 3 weeks. No oral β-blocker therapy was reintroduced, and thereafter, keratoconjunctivitis sicca was well-controlled with topical therapy.