Combining doxycycline and sucralfate? Drug interactions are important to consider
The purpose of this study was to determine the effect of concurrent sucralfate (tablet or suspension) on doxycycline pharmacokinetics and to determine the effects of delaying sucralfate by 2 h on doxycycline absorption. Five dogs were included in a crossover study receiving: doxycycline alone; doxycycline concurrently with sucralfate tablet; doxycycline followed 2 h by sucralfate tablet; doxycycline concurrently with sucralfate suspension; and doxycycline followed 2 h by sucralfate suspension. Doxycycline plasma concentrations were evaluated with liquid chromatography with mass spectrometry. No interaction was seen when sucralfate was administered as a tablet. Sucralfate tablet fragments were frequently observed in some dogs' feces. The area under the curve (AUC) and maximum plasma concentration (CMAX) were significantly lower (P < 0.001) in the concurrent sucralfate suspension group (AUC 7.2 h·μg/mL, CMAX 0.43 μg/mL) than with doxycycline alone (AUC 36.0 h·μg/mL, CMAX 2.53 μg/mL) resulting in a relative bioavailability of 20%. Delaying sucralfate suspension by 2 h after doxycycline administration resulted in no difference in doxycycline absorption as compared with doxycycline administration alone with a relative bioavailability of 74%. The lack of an interaction with sucralfate tablets suggests sucralfate should be administered as a suspension rather than tablet in dogs.
Click here to be directed to the full study from the Journal of Veterinary Pharmacology and Therapeutics.
