Gastric retention of enteric-coated aspirin tablets in beagle dogs

Administration of acetylsalicylic acid (ASA) in the dog may cause gastric mucosal damage. Enteric-coated tablets protect the canine stomach during oral ASA medication. A therapeutic plasma salicylate concentration can be attained using enteric-coated ASA tablets at a dose rate of 25 mg/kg body wt, administered every 8 h. Six beagle dogs were given enteric-coated ASA tablets (500 mg) orally, in a 5-day cross-over experiment on two different feeding regimens: i.e. feeding once daily (Group I) or 8 hourly (Group II). Results demonstrate that feeding regimen strongly influences the plasma salicylate concentration pattern. Subtherapeutic mean plasma salicylate concentrations were found in both groups. In Group II the standard deviation (SD) of the mean plasma salicylate concentration was larger than that of Group I. The minimal plasma salicylate concentration never reached detectable levels in Group II. In both groups large numbers of tablets were vomited. Gastric evacuation of the ASA tablets is comparable to indigestible solid particles; their removal was dependent on the interdigestive gastric motility. It is concluded that large enteric-coated ASA tablets are not suitable for therapeutic use in small dogs.