what are the most effective treatment options for feline herpesvirus-1 ocular and respiratory disease?

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Famciclovir at 90 mg/kg PO q8h is the most evidence-supported systemic antiviral for feline herpesvirus type 1 (FHV-1) ocular and respiratory disease, producing marked clinical improvement in 51% of cats and mild improvement in 34%, for an overall response rate of 85%, with a median time to improvement of 13 days (range 3–183 days).1 The high dose (approximately 90 mg/kg) produces significantly shorter time to improvement and significantly greater degree of improvement than the low dose (approximately 40 mg/kg).1 Most cats (75%) require only one course of treatment, and 53% of owners rate improvement as permanent.1 In shelter kittens with infectious upper respiratory and ocular disease, combining famciclovir 90 mg/kg PO q8h with doxycycline is supported by the most recent controlled data. Famciclovir should be administered by crushing the tablet and combining it with doxycycline suspension immediately before dosing — pre-mixed compounded oral suspensions show poor accuracy, precision, and consistency of formulation and should not be used.6 Doses should be adjusted weekly as kittens gain body weight.6 At 90 mg/kg in a 1 kg kitten, the daily drug cost was approximately US$0.33 at the time of the study.6 For topical ocular antiviral therapy, cidofovir 0.5% ophthalmic solution applied twice daily is the strongest option currently supported by clinical data. Topical cidofovir significantly decreased conjunctival FHV-1 viral load from Day 1 to Day 8 compared with placebo, and 77% of corneal ulcers in antiviral-treated cats healed versus 0% in placebo cats over 7 days.13 Cidofovir also produced significant weight gain in juvenile cats compared with placebo.13 Topical ganciclovir 0.15% gel applied q8h is well tolerated in cats and achieves 100% reduction in viral plaque number in vitro at 89 µM, and it produced significant weight gain in juvenile cats, but did not significantly reduce viral load or improve ocular scores compared with placebo in the 7-day shelter trial.1113