Theophylline pharmacokinetics during hyperbaria and hyperbaric hyperoxia in the dog

The effect of hyperbaria and hyperbaric hyperoxia on the disposition kinetics of theophylline were investigated in the dog. The drug was administered as a 5 mg/kg iv bolus at 1 atmospheres absolute (ATA), 2.8 ATA and 6 ATA. Serial blood samples were collected over an eight hour period and analyzed for theophylline concentration using a gas chromatographic method. From the resultant data, elimination half-life, volume of distribution and total body clearance were calculated. There were no apparent effects of hyperbaria or hyperbaric hyperoxia on any of the parameters describing theophylline disposition, implying that, in the animal model studied, distribution, elimination and effect should remain constant.