Effect of a Cola Beverage on the Bioavailability of Itraconazole in the Presence of H2 Blockers

Thirty-three healthy individuals participated in an open-label, randomized, three-way crossover study designed to compared the bioavailability of a single 200-mg oral dose of itraconazole when administered alone or after treatment with ranitidine, both with and without coadministration of a cola beverage. Each treatment phase was separated by a 2-week washout period. Participants pretreated with ranitidine were required to have a gastric pH of at least 6.0 before receiving itraconazole. An analysis of the area under the curve (AUC) and peak plasma concentration (Cmax) data indicated that the bioavailability of itraconazole was significantly reduced when the gastric pH was increased by pretreatment with ranitidine but showed that this effect was counteracted by the coadministration of an acidic solution (e.g., a cola beverage) that transiently reduced the gastric pH. These findings suggest that the coadministration of an acidic beverage with itraconazole may be an effective approach in improving the bioavailability of itraconazole in patients who are hypochlorhydric or who are taking gastric acid suppressants.