Amoxicillin intestinal absorption reduction by amiloride: Possible role of the Na+-H+ exchanger

✍ Scribed by Westphal, Jean-Frédéric; Jehl, François; Brogard, Jean-Marie; Carbon, Claude

• Book ID: 103037270
• Publisher: Nature Publishing Group
• Year: 1995
• Tongue: English
• Weight: 744 KB
• Volume: 57
• Category: Article
• ISSN: 0009-9236
• DOI: 10.1016/0009-9236(95)90150-7

✦ Synopsis

Intestinal absorption of g-lactam antibiotics has been shown to use the dipeptide carrier system. In vitro experiments have established that the efficiency of uptake by enterocytes depends on an inwardly directed proton gradient-dipeptides and g-&tam antibiotics being cotransported along with hydrogen ion. This gradient is thought to result from the sodium-hydrogen (Na+-H+) exchanger located on the brush-border membrane. The aim of the present study was to assess the iu vivo relevance of these data in humans by ex amining the effect of amiloride, a well-known inhibitor of the Na+-H+ exchanger, on the bioavailability of amoxiciBin in eight healthy volunteers. The results show that amiloride reduces significantly amoxiciBin absorption rate (mean time to maximum concentration increases fkom 1.0 to 1.6 hours, p < 0.05) and absolute bioavailability (by 2796, p < 0.01) and that amiloride-induced inhibition of the intestinal Na+-H+ exchange could be associated with an additional inhibitory effect on (Na/K)-ATBase activity. The present data seem to congrm the role of Na+-H+ exchange in the uptake of glactams by the intestine and to support the indirect sodium dependence of this carrier system in vivo.