Ultrasonographic Evaluation of Vincristine-Induced Gastric Hypomotility and the Prokinetic Effect of Mosapride in Dogs

Vincristine induces gastrointestinal motility disorders in humans. Adverse gastrointestinal events are commonly observed in dogs receiving vincristine. Objectives: To evaluate gastric motility after vincristine administration in dogs and the prophylactic effect of a prokinetic agent, mosapride. Animals: Five healthy Beagle dogs. Methods: Five dogs received vincristine IV at a dosage of 0.75 mg/m ². The motility index (MI) of the antral contraction was ultrasonographically evaluated 30 minutes postfeeding before administration of vincristine and for 6 days after vincristine treatment. After a 6-week washout period, the dogs received vincristine with mosapride (2 mg/kg PO, q24h for 6 days), and the MI was re-evaluated. Adverse gastrointestinal events were evaluated according to the Veterinary Co-operative Group Common Terminology Criteria for Adverse Events (VCOG-CTCAE). Results: After vincristine administration, a significant decrease (P < .05) in MI was observed on days 3 (6.64 ± 0.30) and 4 (8.02 ± 0.94), compared with pretreatment levels (10.00 ± 0.62). Gastrointestinal adverse events were observed in 4 dogs (grade 2 decreased appetite: 3 dogs; grade 1 vomiting: 2 dogs; and grade 1 diarrhea and grade 2 hematochezia: 1 dog). When mosapride citrate was administered with vincristine and for the next 5 days, no decrease in MI was observed. Furthermore, adverse gastrointestinal events occurred less frequently (grade 1 vomiting and grade 2 hematochezia in 1 dog each). Conclusions and Clinical Importance: Vincristine (0.75 mg/m ²) induces gastric hypomotility in dogs. Preventive administration of mosapride citrate (2.0 mg/kg PO, q24h) improves hypomotility and may decrease the adverse gastrointestinal effects of vincristine.