Trimethoprim-sulfonamide combination administered orally and intravaginally in the first trimester of pregnancy: its absorption into serum and transfer to amniotic fluid.

Abstract

Abstract. The absorption of trimethoprim‐sulfonamide combination into serum and transfer to the amniotic fluid after oral and intravaginal administration was studied on 134 patients undergoing legal abortion. The combination given orally as a single dose was absorbed rapidly: the peak levels of both trimethoprim and sulfamethoxazole in serum were reached within 4 hours. In amniotic fluid, the peak level of trimethoprim appeared within 14 hours and that of sulfamethoxazole within 10 hours. After a single intravaginal application of cream, the absorption of trimethoprim into serum and transfer to the amniotic fluid was smaller although measurable amounts could be demonstrated. After repeated intravaginal application during several days no accumulation of trimethoprim in serum or amniotic fluid could be detected.