title: Plasma and urine levels produced by an oral dose of ampicillin 0.5 G administered to women taking oral contraceptives.
abstract: Earlier studies have shown that ampicillin produces 50% lower-and therefore very likely less adequate-plasma levels in pregnant than in nonpregnant women. The present investigation compares levels of ampicillin in plasma and urine produced by a single oral dose administered to 10 healthy women taking oral contraceptives on the 21st and on the 28th day of the menstruation cycle. Plasma levels of ampicillin were lower on the 21st day than on the 28th, i.e. a difference in the same direction as between pregnant and nonpregnant women although the difference was not significant. Contrary to what was found for pregnant women the dose of ampicillin to women taking oral contraceptives does not have to be doubled in order to compensate for lower plasma levels.
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000667:Ampicillin / Q000008:administration & dosage / Q000378:metabolism*; D003276:Contraceptives, Oral / Q000494:pharmacology*; D005260:Female; D006801:Humans
chemical_list: D003276:Contraceptives, Oral; D000667:Ampicillin