CIMETIDINE FOR THE TREATMENT OF MELANOMAS IN HORSES - EFFICACY DETERMINED BY CLIENT QUESTIONNAIRE

A client questionnaire was developed in order to determine the efficac y of oral cimetidine for the treatment of melanomas in the horse. Twel ve horses were identified by a search of hospital records and communic ations with local veterinarians that had been treated for melanomas wi th cimetidine during the period of January 1, 1989, to December 31, 19 91. Owners were contacted and questioned regarding the signalment of t he affected horse, history of the disease, clinical signs, cimetidine usage, and response to therapy. Responders were defined as horses demo nstrating a reduction in size or number of visible or palpable melanom as while undergoing cimetidine therapy. Four horses demonstrated a res ponse to cimetidine therapy. There were no significant differences bet ween responders and non-responders with respect to signalment, history of melanoma origin and growth, distribution and size of melanomas, do sage and duration of cimetidine treatment, or concurrent treatment wit h other medications. It was concluded that cimetidine therapy may affe ct a modest reduction in melanoma size and number in some horses. The factors associated with response in individual animals, however, could not be identified in this study.