Differential Effect of Sodium Bicarbonate on Disposition of Sulfadimethoxine and Sulfisoxazole in Rabbits

Abstract

The orally co-administered sodium bicarbonate significantly enhanced the blood concentration of sulfadimethoxine at the early stage after oral administration to rabbits, by increasing its intestinal absorption. On the other hand, the sodium bicarbonate significantly reduced the blood concentration of sulfisoxazole at the elimination phase after oral administration to rabbits, by increasing its urinary excretion. The fact that sodium bicarbonate exhibits different effects in the disposition of these two sulfonamides is an interesting example to gain a better understanding for the complexity of drug interaction.