Are there any interactions between Prevacid and Allegra?
Saturday, July 10th, 2010 at
2:38 am
I believe there’s some interaction between Allegra and antacids. I was given Prevacid for GERD symptoms but still need Allegra for allergies, didn’t have a chance to discuss this with my doc.
Filed under: Gerd Symptoms
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quick answere is no, if anything it just helps it obsorb into your system. technical answers can be found in medical articles.
Technical answer:
Coadministration with erythromycin has been shown to increase the oral bioavailability of fexofenadine. The proposed mechanism is erythromycin inhibition of the intestinal efflux of fexofenadine via P-glycoprotein transporter. In addition, erythromycin may decrease biliary excretion of fexofenadine. In 24 healthy volunteers, coadministration of fexofenadine 120 mg twice a day and erythromycin 500 mg every 8 hours resulted in a 82% and 109% increase in the steady-state fexofenadine peak plasma concentration (Cmax) and systemic exposure (AUC), respectively, compared to administration of fexofenadine alone. However, no increase in adverse effects or QTc interval were noted. No studies have been performed using clarithromycin or troleandomycin, but similar results are possible given their similarities to erythromycin. Fexofenadine had no effect on the pharmacokinetics of erythromycin.
An in vitro study has recently suggested that a proton pump inhibitor, omeprazole, is a modest substrate of P-glycoprotein. Several studies have shown P-glycoprotein is involved in the absorption and excretion of fexofenadine. Therefore, we examined the effect of fexofenadine on the pharmacokinetics of omeprazole. Eight healthy volunteers participated in this study. They received a single oral dose of 40 mg omeprazole before and after 60 mg fexofenadine (10 doses over 6 days). Blood samplings were performed up to 8 hr after each dosing. Plasma concentrations of omeprazole and its two metabolites were quantified with high-performance liquid chromatography. In addition, the effect of fexofenadine on P-glycoprotein function was examined by flow cytometry using rhodamine 123 and CD56-positive lymphocytes. Comparison of the pharmacokinetic parameters of omeprazole before and after fexofenadine revealed that there were no differences in peak concentration, time to peak concentration, area under the time concentration curve up to 8 hr, and elimination half-life. There were also no differences in these pharmacokinetic parameters for the two metabolites of omeprazole. Flow cytometric analysis revealed that fexofenadine did not inhibit the efflux of rhodamine 123. This study indicated that there was probably no drug interaction between omeprazole and fexofenadine, which might be due to less contribution of P-glycoprotein to omeprazole absorption, insufficient inhibitory effect of fexofenadine on P-glycoprotein, or the involvement of other transporters such as organic anion transporting polypeptides.
(Lansoprazole is a proton pump inhibitor (PPI) in the same pharmacologic class as omeprazole. )
Call your pharmacist. They will actually know more about it than your doctor.