Background: In dogs, delayed gastric emptying (GE) can occur following abdominal surgery or inflammation. While orally administered acetaminophen (AAP) can be used to assess GE, there are currently no clinically applicable methods to document the occurrence of gastroparesis in dogs.
Objectives: To evaluate the effects of gastric prokinetics on GE of liquids in dogs treated with clonidine, an alpha-adrenergic agonist that delays GE, using AAP as a plasma tracer. Animals: 8 healthy purpose-bred dogs
Methods: Prospective cross-over study. In a randomized sequence over 6 weeks, each dog received either no treatment, clonidine (0.03 mg/kg SC), azithromycin (2 mg/kg IV) and clonidine, or metoclopramide (0.5 mg/kg SC) and clonidine 1h before ingesting a liquid meal supplying 25% of the dog’s RER mixed with acetaminophen (20 mg/kg). Blood samples were collected preprandially and at 10 time points between 0.5 and 24 hours. Plasma AAP concentrations were obtained using reverse-phase HPLC. Times to maximum AAP concentration (Tmax) were calculated to estimate GE time, and a 2-way ANOVA with Sidak-adjusted multiple comparisons was performed.
Results: Clonidine treatment significantly delayed Tmax (p< 0.05). Additional therapy with prokinetics metoclopramide or azithromycin did not shorten Tmax. Conclusions and clinical importance: AAP can be used to evaluate GE of liquids. Clonidine increased Tmax for AAP, presumably due to its delaying effect on GE. The clonidine model may not accurately replicate the mechanisms underpinning delayed GE in dogs. However, the documented lack of impact of gastric prokinetics in this study casts some doubt on their effect in clinical cases.
