Gastrointestinal toxicity after vincristine or cyclophosphamide administered with or without maropitant in dogs: a...

To assess the prevalence of gastrointestinal toxicity in dogs receiving chemotherapy with vincristine and cyclophosphamide and the efficacy of maropitant citrate (Cerenia™, Zoetis) in reducing these events.

Dogs receiving chemotherapy with cyclophosphamide or vincristine were randomised to either receive maropitant or not in the period immediately after treatment and for 4 days afterwards. Owners completed a diary of adverse events following treatment.

Adverse events occurred in 40/58 (69%) dogs in the vincristine group. Most of these adverse events were mild and included: lethargy (62%), appetite loss (43%), diarrhoea (34%) and vomiting (24%). Adverse events occurred in 34/42 (81%) dogs treated with cyclophosphamide. Most of these adverse events were mild and included: lethargy (62%), diarrhoea (36%), appetite loss (36%) and vomiting (21%). There was no difference in total clinical score, vomiting, diarrhoea, appetite loss or lethargy score between dogs treated with maropitant and non-treated dogs in either the vincristine or cyclophosphamide groups.

Chemotherapy-related side effects are frequent but usually mild in dogs receiving vincristine or cyclophosphamide. Prophylactic administration of maropitant does not reduce the frequency of adverse events and maropitant should be administered only as required for individual cases.