Drug Interaction Report

GENERALLY AVOID: Coadministration with antacids, H2-receptor antagonists, proton pump inhibitors, or other agents with acid neutralizing or reducing effects may decrease the oral bioavailability and plasma concentrations of ampicillin from bacampicillin. The exact mechanism of interaction is unknown but may be related to degradation of the prodrug when gastric pH is increased.

MANAGEMENT: The possibility of a reduced or subtherapeutic response to bacampicillin should be considered during coadministration with antacids, H2-receptor antagonists, proton pump inhibitors, or other agents that can increase gastric pH. Preferably, these agents should be avoided during therapy with bacampicillin, or an alternative antibiotic be prescribed if these medications cannot be discontinued. Patients treated with antacids (or oral medications that contain antacids such as didanosine buffered tablets or pediatric oral solution) may minimize the effects of the interaction with bacampicillin by separating the times of administration by at least 2 hours.

H2 antagonists may reduce the clearance of nicotine. Cimetidine, 600 mg given twice a day for two days, reduced clearance of an intravenous nicotine dose by 30%. Ranitidine, 300 mg given twice a day for two days, reduced clearance by 10%. The clinical significance of this interaction is not known. Patients should be monitored for increased nicotine effects when using the patches or gum for smoking cessation and dosage adjustments should be made as appropriate.