Drug Interactions between amoxicillin / omeprazole / rifabutin and cefuroxime

GENERALLY AVOID: The coadministration with H2-receptor antagonists, proton pump inhibitors, or other agents that can increase gastric pH may reduce the oral bioavailability of cefpodoxime proxetil and cefuroxime axetil. The proposed mechanism is a pH-dependent reduction in drug dissolution and absorption. In ten healthy volunteers, famotidine 40 mg administered one hour before the ingestion of cefpodoxime proxetil 200 mg led to an approximately 40% reduction in the cefpodoxime peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) compared to when the drug was given alone. Similar results were reported with ranitidine in another study, where cefpodoxime Cmax and AUC decreased by approximately 30%. Likewise, pretreatment with ranitidine plus sodium bicarbonate decreased the Cmax and AUC of cefuroxime by over 40% in six healthy volunteers. The clinical significance of these effects is unknown, but potentially reduced antibiotic efficacy should be considered.

MANAGEMENT: Until further data are available, patients treated with cefpodoxime proxetil or cefuroxime axetil may want to avoid using H2-receptor antagonists, proton pump inhibitors, or other agents that can increase gastric pH. An alternative antibiotic may be considered if these medications cannot be discontinued.