Animal model for theophylline--cimetidine drug interaction.

Cimetidine (300 mg I.V.) and theophylline (15 mg/kg I.V.) were studied in Beagle dogs for possible drug interaction. The drugs were administered alone and in combination using a crossover design. Although none of the determined pharmacokinetic parameters for theophylline changed significantly in the presence of cimetidine, a trend towards significance was found for the terminal half-life, area under the curve, and mean residence time. The magnitude in changes found in Beagles is representative of the changes reported in man.